VOL. I. JANUARY, 1869. No. I. Gold and Stock Telegraphy. AN important invention in telegraphy, patented April 21st, 1868, by B. A. CATLAUAN, has been recently put in operation under the auspices of a company terme the Gold and Stock Telegraph Company, with a central office at No. 18. New street. The practical value of the invention consists in the ability of the instrument and its connections, with two operators at the main office, to transmit to any point, instantane- ously with the bid, sale, offer, or quotation, as correct reports thereof as can be made by experienced reporters in the Boards. The company will not, however, be responsible for losses incurred in any transactions based upon their reports, and only proposes to trans- mit the information; any loss to the stock operator who buys or sells thereupon accruing to account of his own deficit. The advantage of the invention, therefore, consists solely in reporting to every broker or banker who avails himself of it im mediate intelligence at his own office of the ope- rations of the Boards so that it is quite im- possible for any person at the Boards, upon any rise or fall of stocks, to take advantage thereof in buying or selling be- fore the intelligence shall have been trans- mitted to other parties; and, as this has been a very common practice, the effect of the inven- tion is to work a revolu- tion in this respect in stock-jobbing opera - tions. The general working of the plan is very sim- ple. The companys re- porters at the Boards transmit directly to the main of description, and really exactly cotemporary in office by telegraph the operations of the Boards, and point of time. A turn of the hand of the second dial all sales, bids, offers, and demands for stocks as they of the transmitter or indicator, by means of a crank, are called on the list. For instance, if gold is called as in the first case, until it rests upon the first figure at the Board, any variation in its price, or rather the price itself, is in pos- session of all lead- transmits to the central office the abbreviation, with Arabic numerals, on a line beneath the given abbrevi- the figures indicating the quotation, which are re. ation, thus facilitating ease in reading and correcting ceived at that office on indicators, which are connected any liability to mistake. -with the delivery instrument by the operator. In In the cuts accompanying, Fig. 1 represents the other words, the operator receives the instrument; Fig. 2, the quotations, and transmits them by turn- 11 I I I ~ case, which is really an ing the hand of the indicator marked ornamental bit of furni- with letters to the given letter, which is tare for any bankers transmitted by the or nary telegraphic back office; and Fig. 3 means of maiipulation, namely, by press- exhibits the transmitter, ing upon the governor with the finger; which is located at the a second turn of the hand to a second main office. given letter, a second pressure of the fin- Figure 1 is a very ger, and a second letter follows the Jirst, simple and ingenious and so until the given abbreviation has printing telegraph in- been spelled by telegraph. This is the strument, a perfect au first operation, though only first in point tomaton in its opera tions, so far as the office in which it is put up is concerned, and wholly governed by the move- ments of the hands of the transmitter, (Fig. 3,) which appears in the main office, and is han- dled by the operator there. It requires no re- ceiving or transmitting operator, being simply connected with a main line of intelligence. Figure 2 is simply a case for tue instrument represe teC fzs Figure 1, and has tile ~ppearance of a haif height clock of the oU fashion. Be- neath t~ e square box at ~he top, in which is lo- cated the printing in- strument, appears the tape or paper reel, and from the right-hand side is disgor~,ed the printed slip which indicates the abbreviations and their quota- tions in the order called at the Boards, and as there reported. The case is about four and a half feet high, of the form indicat FIG.3 ed in the cut, and may be made just as ornamental with carvings as the re- ceiver may wish. It is to be under- stood that Fig. 3 only appears at the central office, and is for the use of the operator located there; while Fig- ures 1 and 2 are located in the office of the given broker or banker, any number of squares off. The operator at the main office is, therefore, morally re- sponsible for any errors in transmission, unless that ing bankers and brokers on the in- stant; and hence the variation can not be made use of in buying or selling before the intelli- gence of it shall have been generally diffused. The ordinary system of the quotation, ~ pressure of the finger, and the of abbreviation is used. For instance, W. U. for given figure is transmitted. The process is continu- Western Union, and so on through the whole list ed for every figure until the whole quotation has called at the l3oards. The operator at the Board been sent. The quotation is iuarked on the tape in is -~ w. ~ ~ (XFG~S$L~L4I75Pi~ Ticie Manuiactu~er and Builder. error should. arise either from imperfect working of his instrument, or from imperfect working of the printing instrument appearing in the upper section of the case. To detect any error arising from the former cause, the end of the main line is connected with a printing instrument located upon the same table (at the central office) with Figure 8, which is the transmitter; and a second operator is employed to receive and record the quotations at the main office, to the end that any aberration in the action of the transmitter may be detected before it shall have caused damage. This record can be compared at the moment with the transmissions from the Boards direct, and thus any false report may be immediately corrected by a re-transmission from the main office. For aberrations of the printing instrument in the various sub-offices, arising from possible imperfect working, there is, of course, no remedy except to re- port it to the company, which supplies paper and ink and keeps the instrument in order, if so stipulated, at a salary from the banker of six dollars per week. The cost of the instrument to the broker is one hundred and fifty dollars, the company furnishing full reports of the operations of both Stock Boards and Gold Room as they occur. Prices from the Long Room are also included. The company went into operation Novem- ber 23d, 1868, and has already put up about four hun- dred instruments. Persian Arms, Damask Steel, and Damaskeening. THE methods of the celebrated Persian gun-manu- facturer, MIJSTAPITA, are still pursued by his success- ors. The muskets of that famous armorer are worth at present, it is said, from $400 to 500 apiece, though the modern rifles, made on his system, can be bought for $40 to $80, and pistols for $18 to $40. These weapons are generally provided with locks, but sometimes, even at the present day, fired with a fuse. The infantry of Southern Persia is armed with them. They are chiefly manufactured at Laar. When used, they are partly supported by a kind of fork, fastened on the extremity of the barrel. The percussion guns used in Persia are of European manufacture, and the most expensive of them, which are bought by the no- bility only, come from England. Cheaper ones, for the common people, come from Belgium. The Per- sians are good shots, but not sportsmen in the Eng- lish sense. They do not shoot well on the wing. The superiority of the native guns, which we may call the MIJSTAPHA guns, resides, of course, wholly in their barrel, since, as we have said, they have not ad- vanced in other respects beyond the flint-lock. The process of MTJSTAPHA, which was not unlike that em- ployed by English and American armorers in the production of stub-and-twist barrels, may be de- scribed as follows: For the making of a gun, two old horseshoes are taken, together with small pieces of old iron, the whole weighing not quite two pounds. In the heat- ing the small pieces are arranged in such a manner that the horseshoes form the outer rim. When a pro- per degree of softness has been attained, they are welded on an anvil. This process is repeated for sev- eral times, until the iron obtains a length of two feet and a quarter. When twelve such bars are obtained, they are bound together and then welded; the bar obtained is cut in pieces of such a size that four or six will form the desired weapon. These bars are then txvisted and welded together, the resulting piece is afterward bent and again welded to one bar, which finally is turned and bored. If the barrel proves sa- tisfactory, it is polished, in order that the various twist marks may appear which are reduced by the different qualities of iron. It is afterward coated with a paste of two parts of sublimed sulphur mud one part of sea- salt, and left for twenty-four Ii urs in a warm room, and being cleansed is then ready for sale. Other Persian arms, such as swords, etc., consist of iron, ordinary steel, or damask steel. There are four principal varieties of the latter mat~rial, the ma- nufacture of which is peculiarly a Persian industry. The finest, or at least the most expensive, is that of Arsindyan, Neres, and Schiras, three localities former- ly celebrated for this prodmiict. All their furnaces were, however, long ago destroyed and never rebuilt. A blade of Schiras, Neres, or Arsindyan steel is now worth an equal weight of gold. The damask steel of Khorassan is also much sought after for its excellent quality, peculiar dark designs, and great brilliancy. NADER CHAR destroyed the furnaces of Khorassan, and its manufacture has never been revived. Probably most of our readers never heard of Khorassan at all, except as the home of MooREs Vein Prophet. The damask of Kaswine is inferior to the foregoing, but reflects a lustre like gold. The designs in most damask steel are interlinked circles. The manufac- ture at Kaswine is still continued, and the process is like that described below, except that the heads of old horseshoe nails are employed instead of common iron. One of the ordinary varieties of damuash is the Indian. It is made at Lucknow, but the workmen are all Per- sians. Tbis damask consists of three parts silicate of iron, one part cast iron, and two parts very pure iron. These substances are put in crucibles which contain fi~re to forty mislcals, (25 to 200 grammes;) the latter are then set in a furnace, and kept therein for six days at a strong heat. Such furnaces are made to contain from 10,000 to 12,000 crucibles., When the metal is solidified, they are broken to pieces, the iron being brought into an annealing even and kept therein for forty-eight hours, where it is left to cool slowly. If this precaution is neglected, the damask becomes brit- tie as glass does, and is then useless. Damask steel is highly esteemed by the armorers. In order to test its quality, they heat a piece to red heat and forge it to a length of a foot and a half. The occurrence of scintillation, and the failure of the sur- face to preserve perfect evenness, are regarded as in- dications of defective quality in the steel. In the manufacture of swords, a steel bar is first forged by the smith and tile necessary shape given to it. It then passes into the hands of the armorer, who sumoothes it down with the aid of a damask plane. After having been heated, it is planed the second time. Indeed, this process is repeated still further, being brought, at the last, to a very high heat. In order to determine whether the blade has been subjected to the necessary degree of heat, it is polished in part by means of a paste made of fat and emery dust. If the result of the test is satisfactory, the entire blade is pol- ished. If not, it is rdpeatedly exposed to the action of heat until the desired result is obtained. The blade is now immersed in fat and then again exposed to the fire. After this it is filed, and then finally passed into the hands of the polisher. The manufacture of dam- ask swords is, therefore, somewhat complicated, and requires very skillful workmen; nor is it indeed in the end easy to ascertain the quality. When the back of the blade, which is commonly first examined, does not show the least indication of a flaw, it is taken as a good sign; still better if, upon close examination, the sides show no marks of the welding. Moreover, a large experience is necessary to the proper testing of blades, and this is possessed only by the Persians. They are very seldom deceived. Dn RodE HODART relates an instance in which several swords were approved by different parties at different times. They all agreed as regards their estimates of the value of each indivi- dual blade, notwithstanding the surprising fact that their price varied from ten to six hundred dollars. It is a muatter of astonishment that time Persians have shown almost a total disregard of their iron and coal deposits. Thougim, in one instance, they have made a beginning in the smelting of native ores, it is of too little account to be worthy of note. The iron used iii~ their manufactures is nearly all imported. Damaskeening is another branch of industry in Per- sia wlmich bears a very close resemblance to the manu- facture of arms. It is made up of mosaic work, en- graving, and carving. Gold and silver are commonly used in the work of inlaying. This process of da- maskeening of weapons seems, as it were, to have been almost a matter of necessity with the orientals. They commonly used gold in this decorative art, except when the muaterial to be inlaid consisted of copper; that being the case, silver was employed. In some designs both gold and silver were used in the process of orna- mentation. The workmen of the present, however, do not possess the skill of those that preceded them~ and seek to compensate timerefor in show. Blades of late manufacture do not, however, lack in elegance. The Persian weapon is easily recognized; so easily, in fact, that there is no need of the manufacturers stamping his muark upon it. The Persians can be said to have a style of their own only in so far as they have carried out to completeness the ideas of others. As to origi- nality, they nan lay but very little clain{ to it. The space used for designs being naturally quite limited, opportunity is not offered for very extensive work. Swords are rarely damaskeened. They bear two marks: one, the name of the maker; the other, a verse of the Koran. Damaskeening is more frequent in the case of daggers, and other weapons, of like character, worn in the belt. There are three kinds of damaskeening: The first is employed when designs in relief is the object in view. The design is first drawn by means of a brush; it is afterward engraved, and then filled in with small gold wires. These wires are so large as to project some- what above the surface of the instrument. They are fastened at different points with golden nails. The details are carried out in time work of engraving. If, for instance, a bird is to be represented, the part inlaid with gold shows only the general outline. The de- tails, as, for example, the eyes and feathers, are en- graved. In the case of the second method there is no relief. The ornamentation is made to conform to the surface of the weapon. The gold is pressed into its bed by means of a stonenephriteand is afterward polished to a smooth surface by means of a paste, comuposed of eme- ry dust and olive oil. The third process is the one in common use. It is employed for metals only. Minerals or ivory, since they would break under the blows of the hammer, can not be used in the employment of this method. In- stead of carving the design, as is done in the two first instances, it is only indicated in outline. Timen, by means of a peculiar instrument, it is covered over with holes scarcely visible. Gold, in the form of exceeding- ly fine pieces of wire, is then pressed into them. The weapon is afterward heated and the surface polished with nephrite. This operation having been repeated, the surface is rubbed with a paste of emery and oil The best workmen are found in Ispahan. The art is, however, very much en the wane, when compared with others. Much skill is, however, even yet shown, both in the character of the designs and in the trans- ferring of the gold. But in our judgment in regard to such works, we must consider, also, the effect of time. The gold used in the decoration of those instruments that have been used for a long time, has, of course, lost its original lustretaken on a duller cast, more in harmony, per- haps, with the general appearance of the weapon than its first splendor. It may he remarked that quite probably the works of olden times owe much of their superiority to the effect of time itself, rather than to the skill of superior workmen. The art of damaskeen- lug is apparently dying out, and ere long will be known only by the works it has left behind, but this is rather an effect of time than want of artistic skill. I-low to Cause a Tempest in a Teapot~ WE mean this literally, net figuratively, as this cx pression is usually employed. Take an earthen or porcelain teapot, fill it one quar- ter or one third full with water, then throw in a few small pieces of phosphorus of about the size of grains of wheat, also about a teaspoonful of chlorate of pot- ash; then take a glass tube, or, in lack of that, a com- mon clay pipe, and press the stem to the bottom of the 2

Ticie Manuiactu~er and Builder. error should. arise either from imperfect working of his instrument, or from imperfect working of the printing instrument appearing in the upper section of the case. To detect any error arising from the former cause, the end of the main line is connected with a printing instrument located upon the same table (at the central office) with Figure 8, which is the transmitter; and a second operator is employed to receive and record the quotations at the main office, to the end that any aberration in the action of the transmitter may be detected before it shall have caused damage. This record can be compared at the moment with the transmissions from the Boards direct, and thus any false report may be immediately corrected by a re-transmission from the main office. For aberrations of the printing instrument in the various sub-offices, arising from possible imperfect working, there is, of course, no remedy except to re- port it to the company, which supplies paper and ink and keeps the instrument in order, if so stipulated, at a salary from the banker of six dollars per week. The cost of the instrument to the broker is one hundred and fifty dollars, the company furnishing full reports of the operations of both Stock Boards and Gold Room as they occur. Prices from the Long Room are also included. The company went into operation Novem- ber 23d, 1868, and has already put up about four hun- dred instruments. Persian Arms, Damask Steel, and Damaskeening. THE methods of the celebrated Persian gun-manu- facturer, MIJSTAPITA, are still pursued by his success- ors. The muskets of that famous armorer are worth at present, it is said, from $400 to 500 apiece, though the modern rifles, made on his system, can be bought for $40 to $80, and pistols for $18 to $40. These weapons are generally provided with locks, but sometimes, even at the present day, fired with a fuse. The infantry of Southern Persia is armed with them. They are chiefly manufactured at Laar. When used, they are partly supported by a kind of fork, fastened on the extremity of the barrel. The percussion guns used in Persia are of European manufacture, and the most expensive of them, which are bought by the no- bility only, come from England. Cheaper ones, for the common people, come from Belgium. The Per- sians are good shots, but not sportsmen in the Eng- lish sense. They do not shoot well on the wing. The superiority of the native guns, which we may call the MIJSTAPHA guns, resides, of course, wholly in their barrel, since, as we have said, they have not ad- vanced in other respects beyond the flint-lock. The process of MTJSTAPHA, which was not unlike that em- ployed by English and American armorers in the production of stub-and-twist barrels, may be de- scribed as follows: For the making of a gun, two old horseshoes are taken, together with small pieces of old iron, the whole weighing not quite two pounds. In the heat- ing the small pieces are arranged in such a manner that the horseshoes form the outer rim. When a pro- per degree of softness has been attained, they are welded on an anvil. This process is repeated for sev- eral times, until the iron obtains a length of two feet and a quarter. When twelve such bars are obtained, they are bound together and then welded; the bar obtained is cut in pieces of such a size that four or six will form the desired weapon. These bars are then txvisted and welded together, the resulting piece is afterward bent and again welded to one bar, which finally is turned and bored. If the barrel proves sa- tisfactory, it is polished, in order that the various twist marks may appear which are reduced by the different qualities of iron. It is afterward coated with a paste of two parts of sublimed sulphur mud one part of sea- salt, and left for twenty-four Ii urs in a warm room, and being cleansed is then ready for sale. Other Persian arms, such as swords, etc., consist of iron, ordinary steel, or damask steel. There are four principal varieties of the latter mat~rial, the ma- nufacture of which is peculiarly a Persian industry. The finest, or at least the most expensive, is that of Arsindyan, Neres, and Schiras, three localities former- ly celebrated for this prodmiict. All their furnaces were, however, long ago destroyed and never rebuilt. A blade of Schiras, Neres, or Arsindyan steel is now worth an equal weight of gold. The damask steel of Khorassan is also much sought after for its excellent quality, peculiar dark designs, and great brilliancy. NADER CHAR destroyed the furnaces of Khorassan, and its manufacture has never been revived. Probably most of our readers never heard of Khorassan at all, except as the home of MooREs Vein Prophet. The damask of Kaswine is inferior to the foregoing, but reflects a lustre like gold. The designs in most damask steel are interlinked circles. The manufac- ture at Kaswine is still continued, and the process is like that described below, except that the heads of old horseshoe nails are employed instead of common iron. One of the ordinary varieties of damuash is the Indian. It is made at Lucknow, but the workmen are all Per- sians. Tbis damask consists of three parts silicate of iron, one part cast iron, and two parts very pure iron. These substances are put in crucibles which contain fi~re to forty mislcals, (25 to 200 grammes;) the latter are then set in a furnace, and kept therein for six days at a strong heat. Such furnaces are made to contain from 10,000 to 12,000 crucibles., When the metal is solidified, they are broken to pieces, the iron being brought into an annealing even and kept therein for forty-eight hours, where it is left to cool slowly. If this precaution is neglected, the damask becomes brit- tie as glass does, and is then useless. Damask steel is highly esteemed by the armorers. In order to test its quality, they heat a piece to red heat and forge it to a length of a foot and a half. The occurrence of scintillation, and the failure of the sur- face to preserve perfect evenness, are regarded as in- dications of defective quality in the steel. In the manufacture of swords, a steel bar is first forged by the smith and tile necessary shape given to it. It then passes into the hands of the armorer, who sumoothes it down with the aid of a damask plane. After having been heated, it is planed the second time. Indeed, this process is repeated still further, being brought, at the last, to a very high heat. In order to determine whether the blade has been subjected to the necessary degree of heat, it is polished in part by means of a paste made of fat and emery dust. If the result of the test is satisfactory, the entire blade is pol- ished. If not, it is rdpeatedly exposed to the action of heat until the desired result is obtained. The blade is now immersed in fat and then again exposed to the fire. After this it is filed, and then finally passed into the hands of the polisher. The manufacture of dam- ask swords is, therefore, somewhat complicated, and requires very skillful workmen; nor is it indeed in the end easy to ascertain the quality. When the back of the blade, which is commonly first examined, does not show the least indication of a flaw, it is taken as a good sign; still better if, upon close examination, the sides show no marks of the welding. Moreover, a large experience is necessary to the proper testing of blades, and this is possessed only by the Persians. They are very seldom deceived. Dn RodE HODART relates an instance in which several swords were approved by different parties at different times. They all agreed as regards their estimates of the value of each indivi- dual blade, notwithstanding the surprising fact that their price varied from ten to six hundred dollars. It is a muatter of astonishment that time Persians have shown almost a total disregard of their iron and coal deposits. Thougim, in one instance, they have made a beginning in the smelting of native ores, it is of too little account to be worthy of note. The iron used iii~ their manufactures is nearly all imported. Damaskeening is another branch of industry in Per- sia wlmich bears a very close resemblance to the manu- facture of arms. It is made up of mosaic work, en- graving, and carving. Gold and silver are commonly used in the work of inlaying. This process of da- maskeening of weapons seems, as it were, to have been almost a matter of necessity with the orientals. They commonly used gold in this decorative art, except when the muaterial to be inlaid consisted of copper; that being the case, silver was employed. In some designs both gold and silver were used in the process of orna- mentation. The workmen of the present, however, do not possess the skill of those that preceded them~ and seek to compensate timerefor in show. Blades of late manufacture do not, however, lack in elegance. The Persian weapon is easily recognized; so easily, in fact, that there is no need of the manufacturers stamping his muark upon it. The Persians can be said to have a style of their own only in so far as they have carried out to completeness the ideas of others. As to origi- nality, they nan lay but very little clain{ to it. The space used for designs being naturally quite limited, opportunity is not offered for very extensive work. Swords are rarely damaskeened. They bear two marks: one, the name of the maker; the other, a verse of the Koran. Damaskeening is more frequent in the case of daggers, and other weapons, of like character, worn in the belt. There are three kinds of damaskeening: The first is employed when designs in relief is the object in view. The design is first drawn by means of a brush; it is afterward engraved, and then filled in with small gold wires. These wires are so large as to project some- what above the surface of the instrument. They are fastened at different points with golden nails. The details are carried out in time work of engraving. If, for instance, a bird is to be represented, the part inlaid with gold shows only the general outline. The de- tails, as, for example, the eyes and feathers, are en- graved. In the case of the second method there is no relief. The ornamentation is made to conform to the surface of the weapon. The gold is pressed into its bed by means of a stonenephriteand is afterward polished to a smooth surface by means of a paste, comuposed of eme- ry dust and olive oil. The third process is the one in common use. It is employed for metals only. Minerals or ivory, since they would break under the blows of the hammer, can not be used in the employment of this method. In- stead of carving the design, as is done in the two first instances, it is only indicated in outline. Timen, by means of a peculiar instrument, it is covered over with holes scarcely visible. Gold, in the form of exceeding- ly fine pieces of wire, is then pressed into them. The weapon is afterward heated and the surface polished with nephrite. This operation having been repeated, the surface is rubbed with a paste of emery and oil The best workmen are found in Ispahan. The art is, however, very much en the wane, when compared with others. Much skill is, however, even yet shown, both in the character of the designs and in the trans- ferring of the gold. But in our judgment in regard to such works, we must consider, also, the effect of time. The gold used in the decoration of those instruments that have been used for a long time, has, of course, lost its original lustretaken on a duller cast, more in harmony, per- haps, with the general appearance of the weapon than its first splendor. It may he remarked that quite probably the works of olden times owe much of their superiority to the effect of time itself, rather than to the skill of superior workmen. The art of damaskeen- lug is apparently dying out, and ere long will be known only by the works it has left behind, but this is rather an effect of time than want of artistic skill. I-low to Cause a Tempest in a Teapot~ WE mean this literally, net figuratively, as this cx pression is usually employed. Take an earthen or porcelain teapot, fill it one quar- ter or one third full with water, then throw in a few small pieces of phosphorus of about the size of grains of wheat, also about a teaspoonful of chlorate of pot- ash; then take a glass tube, or, in lack of that, a com- mon clay pipe, and press the stem to the bottom of the 2

Ticie Manuiactu~er and Builder. error should. arise either from imperfect working of his instrument, or from imperfect working of the printing instrument appearing in the upper section of the case. To detect any error arising from the former cause, the end of the main line is connected with a printing instrument located upon the same table (at the central office) with Figure 8, which is the transmitter; and a second operator is employed to receive and record the quotations at the main office, to the end that any aberration in the action of the transmitter may be detected before it shall have caused damage. This record can be compared at the moment with the transmissions from the Boards direct, and thus any false report may be immediately corrected by a re-transmission from the main office. For aberrations of the printing instrument in the various sub-offices, arising from possible imperfect working, there is, of course, no remedy except to re- port it to the company, which supplies paper and ink and keeps the instrument in order, if so stipulated, at a salary from the banker of six dollars per week. The cost of the instrument to the broker is one hundred and fifty dollars, the company furnishing full reports of the operations of both Stock Boards and Gold Room as they occur. Prices from the Long Room are also included. The company went into operation Novem- ber 23d, 1868, and has already put up about four hun- dred instruments. Persian Arms, Damask Steel, and Damaskeening. THE methods of the celebrated Persian gun-manu- facturer, MIJSTAPITA, are still pursued by his success- ors. The muskets of that famous armorer are worth at present, it is said, from $400 to 500 apiece, though the modern rifles, made on his system, can be bought for $40 to $80, and pistols for $18 to $40. These weapons are generally provided with locks, but sometimes, even at the present day, fired with a fuse. The infantry of Southern Persia is armed with them. They are chiefly manufactured at Laar. When used, they are partly supported by a kind of fork, fastened on the extremity of the barrel. The percussion guns used in Persia are of European manufacture, and the most expensive of them, which are bought by the no- bility only, come from England. Cheaper ones, for the common people, come from Belgium. The Per- sians are good shots, but not sportsmen in the Eng- lish sense. They do not shoot well on the wing. The superiority of the native guns, which we may call the MIJSTAPHA guns, resides, of course, wholly in their barrel, since, as we have said, they have not ad- vanced in other respects beyond the flint-lock. The process of MTJSTAPHA, which was not unlike that em- ployed by English and American armorers in the production of stub-and-twist barrels, may be de- scribed as follows: For the making of a gun, two old horseshoes are taken, together with small pieces of old iron, the whole weighing not quite two pounds. In the heat- ing the small pieces are arranged in such a manner that the horseshoes form the outer rim. When a pro- per degree of softness has been attained, they are welded on an anvil. This process is repeated for sev- eral times, until the iron obtains a length of two feet and a quarter. When twelve such bars are obtained, they are bound together and then welded; the bar obtained is cut in pieces of such a size that four or six will form the desired weapon. These bars are then txvisted and welded together, the resulting piece is afterward bent and again welded to one bar, which finally is turned and bored. If the barrel proves sa- tisfactory, it is polished, in order that the various twist marks may appear which are reduced by the different qualities of iron. It is afterward coated with a paste of two parts of sublimed sulphur mud one part of sea- salt, and left for twenty-four Ii urs in a warm room, and being cleansed is then ready for sale. Other Persian arms, such as swords, etc., consist of iron, ordinary steel, or damask steel. There are four principal varieties of the latter mat~rial, the ma- nufacture of which is peculiarly a Persian industry. The finest, or at least the most expensive, is that of Arsindyan, Neres, and Schiras, three localities former- ly celebrated for this prodmiict. All their furnaces were, however, long ago destroyed and never rebuilt. A blade of Schiras, Neres, or Arsindyan steel is now worth an equal weight of gold. The damask steel of Khorassan is also much sought after for its excellent quality, peculiar dark designs, and great brilliancy. NADER CHAR destroyed the furnaces of Khorassan, and its manufacture has never been revived. Probably most of our readers never heard of Khorassan at all, except as the home of MooREs Vein Prophet. The damask of Kaswine is inferior to the foregoing, but reflects a lustre like gold. The designs in most damask steel are interlinked circles. The manufac- ture at Kaswine is still continued, and the process is like that described below, except that the heads of old horseshoe nails are employed instead of common iron. One of the ordinary varieties of damuash is the Indian. It is made at Lucknow, but the workmen are all Per- sians. Tbis damask consists of three parts silicate of iron, one part cast iron, and two parts very pure iron. These substances are put in crucibles which contain fi~re to forty mislcals, (25 to 200 grammes;) the latter are then set in a furnace, and kept therein for six days at a strong heat. Such furnaces are made to contain from 10,000 to 12,000 crucibles., When the metal is solidified, they are broken to pieces, the iron being brought into an annealing even and kept therein for forty-eight hours, where it is left to cool slowly. If this precaution is neglected, the damask becomes brit- tie as glass does, and is then useless. Damask steel is highly esteemed by the armorers. In order to test its quality, they heat a piece to red heat and forge it to a length of a foot and a half. The occurrence of scintillation, and the failure of the sur- face to preserve perfect evenness, are regarded as in- dications of defective quality in the steel. In the manufacture of swords, a steel bar is first forged by the smith and tile necessary shape given to it. It then passes into the hands of the armorer, who sumoothes it down with the aid of a damask plane. After having been heated, it is planed the second time. Indeed, this process is repeated still further, being brought, at the last, to a very high heat. In order to determine whether the blade has been subjected to the necessary degree of heat, it is polished in part by means of a paste made of fat and emery dust. If the result of the test is satisfactory, the entire blade is pol- ished. If not, it is rdpeatedly exposed to the action of heat until the desired result is obtained. The blade is now immersed in fat and then again exposed to the fire. After this it is filed, and then finally passed into the hands of the polisher. The manufacture of dam- ask swords is, therefore, somewhat complicated, and requires very skillful workmen; nor is it indeed in the end easy to ascertain the quality. When the back of the blade, which is commonly first examined, does not show the least indication of a flaw, it is taken as a good sign; still better if, upon close examination, the sides show no marks of the welding. Moreover, a large experience is necessary to the proper testing of blades, and this is possessed only by the Persians. They are very seldom deceived. Dn RodE HODART relates an instance in which several swords were approved by different parties at different times. They all agreed as regards their estimates of the value of each indivi- dual blade, notwithstanding the surprising fact that their price varied from ten to six hundred dollars. It is a muatter of astonishment that time Persians have shown almost a total disregard of their iron and coal deposits. Thougim, in one instance, they have made a beginning in the smelting of native ores, it is of too little account to be worthy of note. The iron used iii~ their manufactures is nearly all imported. Damaskeening is another branch of industry in Per- sia wlmich bears a very close resemblance to the manu- facture of arms. It is made up of mosaic work, en- graving, and carving. Gold and silver are commonly used in the work of inlaying. This process of da- maskeening of weapons seems, as it were, to have been almost a matter of necessity with the orientals. They commonly used gold in this decorative art, except when the muaterial to be inlaid consisted of copper; that being the case, silver was employed. In some designs both gold and silver were used in the process of orna- mentation. The workmen of the present, however, do not possess the skill of those that preceded them~ and seek to compensate timerefor in show. Blades of late manufacture do not, however, lack in elegance. The Persian weapon is easily recognized; so easily, in fact, that there is no need of the manufacturers stamping his muark upon it. The Persians can be said to have a style of their own only in so far as they have carried out to completeness the ideas of others. As to origi- nality, they nan lay but very little clain{ to it. The space used for designs being naturally quite limited, opportunity is not offered for very extensive work. Swords are rarely damaskeened. They bear two marks: one, the name of the maker; the other, a verse of the Koran. Damaskeening is more frequent in the case of daggers, and other weapons, of like character, worn in the belt. There are three kinds of damaskeening: The first is employed when designs in relief is the object in view. The design is first drawn by means of a brush; it is afterward engraved, and then filled in with small gold wires. These wires are so large as to project some- what above the surface of the instrument. They are fastened at different points with golden nails. The details are carried out in time work of engraving. If, for instance, a bird is to be represented, the part inlaid with gold shows only the general outline. The de- tails, as, for example, the eyes and feathers, are en- graved. In the case of the second method there is no relief. The ornamentation is made to conform to the surface of the weapon. The gold is pressed into its bed by means of a stonenephriteand is afterward polished to a smooth surface by means of a paste, comuposed of eme- ry dust and olive oil. The third process is the one in common use. It is employed for metals only. Minerals or ivory, since they would break under the blows of the hammer, can not be used in the employment of this method. In- stead of carving the design, as is done in the two first instances, it is only indicated in outline. Timen, by means of a peculiar instrument, it is covered over with holes scarcely visible. Gold, in the form of exceeding- ly fine pieces of wire, is then pressed into them. The weapon is afterward heated and the surface polished with nephrite. This operation having been repeated, the surface is rubbed with a paste of emery and oil The best workmen are found in Ispahan. The art is, however, very much en the wane, when compared with others. Much skill is, however, even yet shown, both in the character of the designs and in the trans- ferring of the gold. But in our judgment in regard to such works, we must consider, also, the effect of time. The gold used in the decoration of those instruments that have been used for a long time, has, of course, lost its original lustretaken on a duller cast, more in harmony, per- haps, with the general appearance of the weapon than its first splendor. It may he remarked that quite probably the works of olden times owe much of their superiority to the effect of time itself, rather than to the skill of superior workmen. The art of damaskeen- lug is apparently dying out, and ere long will be known only by the works it has left behind, but this is rather an effect of time than want of artistic skill. I-low to Cause a Tempest in a Teapot~ WE mean this literally, net figuratively, as this cx pression is usually employed. Take an earthen or porcelain teapot, fill it one quar- ter or one third full with water, then throw in a few small pieces of phosphorus of about the size of grains of wheat, also about a teaspoonful of chlorate of pot- ash; then take a glass tube, or, in lack of that, a com- mon clay pipe, and press the stem to the bottom of the 2 The Manufacturer and Builder. teapot, so that any liquid poured in at the top will reach the bottom of the pot at once, without becoming diluted by the water. If sulphuric acid be now poured in slowly, a small quantity at a time, it xviii, as soon as it comes in contact with the chlorate of potash and phosphorus, cause a number of slight explosions, hiss, and make all kinds of noises, and give a literal illus- tration of the so-frequently mentioned phenomenon of a tempest in a teapot. Any glas-i ;c~zel may be sub- stituted for the teapot, and then the action of the chemicals may be observed. The Causes of the Difference in the Colorcf Bricks. A GREAT many erroneous Views exist among manu- facturers in regard to the chemical combinations to which the color of certain kinds of burnt bricks is to be ascribed. Especially strong is the belieg that white or light-colored bricks can only be produced un- der the influence of reducing processes, which would change the peroxide of iron into the protoxide ; al- though it is a well-known fact that the protoxide, in its combinations with other bases, forms a far greater xuiriety of more intensely colored compounds than the peroxide. If it were supposed that the metallic pro- toxide could remain in an uncombined state, a more or less black-colored mass would be the result. It has been surmised that sulphurous acid, resulting from pyritif~rous fuel, was an important agent in these sup- posed deoxidizing processes, although sulphurous acid can never play the part of a reducing agent in the high heat of a brick-kiln. The sulphuric acid, on the con- trary, which might have been contained in the clay, would, under these conditions, through the mere influ- ence of heat, be decomposed into suiphurons gas and free oxygen. On the other hand, it is maintained by some manufacturers that white bricks, which assume a green color when half-fused by high heat, owe this change of color and an increase of absolute weight to an addition of oxygen through the influence of protoxide of iron. In this case, as in the former, the reality of facts has been totally reversed; for, accord- ing to our investigations, the white bricks contain only peroxide of iron, and the green glazed ones, on the contrary, a considerable quantity of protoxide; the latter, thesefore, must have less absolute weight than when they were in the white state, and only the specific gravity of compact pieces has been increased, as, in consequence of a semi-fusion, most of their pores are closed. Some time since, we analyzed several bricks with reference to the above questions, and recently have given this subject renewed thought. The main ques- tion turns upon the determination of the quantity of iron present, and its state of oxidation; since this metal is not only the cause of the various tints, but even of the very existence of color in bricks. The most particular attention, therefore, had to be paid to the determination of the existence of protoxide of iron. This determination, however, presented some difficul- ties, since hard-burnt bricks are the most refractory of all complex silicious substances. Not even the color of pulverized bricks is materially changed by treatment with sulphuric acid, in a closed glass tube, according to Alex. Mitcherlichs method, at 35O~ centigrade, for eight to ten hours. By treating with hydrofin- oric acid, however, a total decomposition is effected, and the protoxide of iron can then be determined In the diluted solution by hypermanganate of potassa. We have made a number of tests to prove that pure hydrofluoric acid (free from arsenic) does not affect the action of the standard potassic solution.. J. COOKE (Journal of Practical Uhemistry, vol. cii., page 456) has also shown that protoxide of iron in a solution of sulphate of iron may be accurately determined in the presence of hydrofluoric acid by hypermanganate of potassa. The specimens which were first subjected to analysis were two kinds of bricks from the works of Mr. OPPENHEThI, near Riidersdorf, and two others from the works of Dr. KUHNHEIM at Freienwalde on t~h~ Oder. The physical properties of these ma- terials and their total contents of iron were as fol- lows: RfiDERSDO1IF J3JtTcKs. No. 1. Pale red outside, more highly colored in- side; moderately hard; manufactured at cherry heat; contain 3.78 per cent of sesquioxide of iron. No. 2. Pale yellowish white, reddish inside; glazed, harder and firmer than No. 1 ; manufactured at a con- siderably higher temperature, verging on that of white heat; contain 4.26 per cent of ~esquioxide of iron. FREIENWALDE ]3lircKs. No. 8. Lively red; moderately hard and firm; manufactured at cherry heat; contains 3.79 per cent of sesquioxide of iron. No. 4. Darker red; more compact and of greater hardness than No. 3; manufactured at a temperature near white heat; contain 4.28 per cent of sesquiexide of iron. All these four specimens showed, during analyses, reactions so slight of protoxide of iron that its exist- ence, or trace even, is dubious. These facts show: 1st. That a relatively small percentage of peroxide of iron is sufficient to impart a lively red color to bricks. 2d. That with a perfectly equal percentage of iron, certain kinds of brick remain red when burned at nearly a white heat, whilst others turn pale without a reduction of their peroxide of iron into protoxide. The last difference is merely based upon a variation in the percentage of lime contained in the raw mate- rial. According to analyses made by Mr. HEY, at the laboratory of the Mining Academy at Berlin, under the supervision of Mr. FINKENEE, the clay of Steinitz- See, from which the Rildersdorf brick are made, con- tains 8.69 per cent, that of Freienxvalde only 2.47 per cent of lime, while the quantities of magnesia and alkalies are very minute and equal in both cases. The oxide of calcium, (lime,) if contained in consider- able quantity in the raw material, acts, under the in- fluence of high heat, upon the peroxide of iron, predis- posing it to enter the combination of a polybasic white silicate. It can not be supposed that a ferrate of lime is formed xvhile silicic acid is present in such decided excess. Besides, the pure compounds of this kind are reddish-brown. The magnesia, which exists mostly in insignificant quantities, does not seem to play an important part. According to the experience of many manufacturers, pale bricks are produced, especi- ally in those parts of the kiln where smoke has had a chance to collect or to touch the clay. The cause of this is the higher local temp~rature, resulting from a more intimate contact with combustible particles. If a brick containing but little lime changes in color from light red to dark red, an alteration only of the physical state of aggregation of the free uncom- blued peroxide of iron takes place; and this substance is the only cause of color in all kinds of brick. My. next communication will treat of green and dark-colored clinkers. How to Make Different Cements. A Cement withstanding Water, Acids, Oils, etc. Simple shellac, made up into sticks of the size of a lead pencil, is commonly sold for such cement. The objects to be cemented together are first warmed till they melt the shellac brought in contact with them. This is very good to cement broken glass, porcelain, etc., especially as the objects are again ready for use immediately when cold; but it is not adapted for flexible objects, as it cracks, and also will not with- stand heat or alcohol, which soften the shellac. A Cement withstanding Heat and AlcoholTake the best kind of glue; pour on an equal quantity of water; let it soak over night; next morning melt it over a gentle heat, and add fine Paris white, or white- lead; mix well, and add a little acetic acid, carbolic acid, oil of cloves, or any other ethereal oil, to prevent 3 putrefaction. This cement will also be adapted for flexible objects, like leather, and is sold at present from wagons in different cities of the United States. This cement xviii not withstand boiling water well, as this softens the glue. A Cement withstanding Heat and 3foisture 7joth. Simply pure white-lead, or zinc-white, ground in oil, andpsed very thick, is an excellent cement for mend- ing broken crockery ware; but it takes a very long time to harden sufficiently. The best plan is to place the mended object in some store-room, and not to look after it for several weeks, or even months.. After that time it will be found so firmly united that, if ever again broken, it will not part on the line of the former fracture. Learned Blacksmiths. Wuo has not heard of the learned blacksmith, En- RU BURRITE? His learning is, however, merely lite- rary and outside of his profession. In his youth little was known of that which at present con~titutes scien- tific, useful, and practical knowledge, and therefore it is not to be wondered at that a man in whom the natural thirst for information, which we observe in all children, has not been suppressed by defective educa- tion and bad company, satisfied this thirst by pure literary pursuits. At the present day it is different Scores of facts in natural science are known, studied, and applied; moi~e interesting, we think, than all the literary productions of Greece and Rome, together with those of some modern nations throxvn in; and a blacksmiths nowadays who wishes to extend the range of his knowledge need not go entirely outside of his occupation to satisfy his praiseworthy desires. An illustration of this was lately given in England, by Mr. SAXBY, xvho applied his knowledge of the pro- perties of magnets, the compass-needle, and the mysto-. rious magnetic properties of the e~trths to the detection of hidden defects in iron castings, wrought-iron shafts, and other heavy products of the iron industry. In order to understand this method, it must first be known that, xvhen a small magnetic steel bar is so supported or suspended by its centre of gravity that, besides being able to turn in a horizontal plane, it can also turn in sectional planes, it will not only point northward, but, at the same time; doxvnward, with an inclination of some seventy degrees. This downward inclination is called the dip of the needle; the end di- rected downward is called the north pole, the upper end the south pole. Secondly, it must be knoxvn that, if an elongated piece of iron is placed in the described position or nearly so, it xvihl become magnetic by the influence of the earths magnetism, and a common compass-needle will indicate this plainly. The loxver portion xviii obtain a so-called polarity, similar to the north pole of the compass-needle; the upper end one similar to the south pole. 1f however, this iron is placed in a horizontal position, pointing nearly east and west, but exactly perpendicular to the direction of this dipping-needle, it must lose this so-called magnetic polarity, especially if it is also thoroughly jarred by hammering. If, now, a compass-needle is passed along this bar, it must shoxv an equal attraction for the needle along its whole length. A flaw or bad place anywhere will be detected by an ir- regularity in the direction of the needle as it is passed over the spot. The inventor of this method xvas put to a severe test in England. In a heavy shaft of iron a large hole was drilled, filled up with an inferior iron, then plugged up, and turned off so smoothly that the place xvhere this had been done could not be detected. Mr. SAxEY found the place with his compass-needle, and stated that at this spot the strength of the shaft was not reliable. In every other case where he indi- cated hidden flaws in iron his statement was verified by subsequent examination. This is only one out of thousands of instances which might be brought forward indicating how the study of modern sciences possesses not only a peculiar charm unknown to those devoting themselves to mere lite- rary pursuits, but also bears practical fruits, beneficial /

The Manufacturer and Builder. teapot, so that any liquid poured in at the top will reach the bottom of the pot at once, without becoming diluted by the water. If sulphuric acid be now poured in slowly, a small quantity at a time, it xviii, as soon as it comes in contact with the chlorate of potash and phosphorus, cause a number of slight explosions, hiss, and make all kinds of noises, and give a literal illus- tration of the so-frequently mentioned phenomenon of a tempest in a teapot. Any glas-i ;c~zel may be sub- stituted for the teapot, and then the action of the chemicals may be observed. The Causes of the Difference in the Colorcf Bricks. A GREAT many erroneous Views exist among manu- facturers in regard to the chemical combinations to which the color of certain kinds of burnt bricks is to be ascribed. Especially strong is the belieg that white or light-colored bricks can only be produced un- der the influence of reducing processes, which would change the peroxide of iron into the protoxide ; al- though it is a well-known fact that the protoxide, in its combinations with other bases, forms a far greater xuiriety of more intensely colored compounds than the peroxide. If it were supposed that the metallic pro- toxide could remain in an uncombined state, a more or less black-colored mass would be the result. It has been surmised that sulphurous acid, resulting from pyritif~rous fuel, was an important agent in these sup- posed deoxidizing processes, although sulphurous acid can never play the part of a reducing agent in the high heat of a brick-kiln. The sulphuric acid, on the con- trary, which might have been contained in the clay, would, under these conditions, through the mere influ- ence of heat, be decomposed into suiphurons gas and free oxygen. On the other hand, it is maintained by some manufacturers that white bricks, which assume a green color when half-fused by high heat, owe this change of color and an increase of absolute weight to an addition of oxygen through the influence of protoxide of iron. In this case, as in the former, the reality of facts has been totally reversed; for, accord- ing to our investigations, the white bricks contain only peroxide of iron, and the green glazed ones, on the contrary, a considerable quantity of protoxide; the latter, thesefore, must have less absolute weight than when they were in the white state, and only the specific gravity of compact pieces has been increased, as, in consequence of a semi-fusion, most of their pores are closed. Some time since, we analyzed several bricks with reference to the above questions, and recently have given this subject renewed thought. The main ques- tion turns upon the determination of the quantity of iron present, and its state of oxidation; since this metal is not only the cause of the various tints, but even of the very existence of color in bricks. The most particular attention, therefore, had to be paid to the determination of the existence of protoxide of iron. This determination, however, presented some difficul- ties, since hard-burnt bricks are the most refractory of all complex silicious substances. Not even the color of pulverized bricks is materially changed by treatment with sulphuric acid, in a closed glass tube, according to Alex. Mitcherlichs method, at 35O~ centigrade, for eight to ten hours. By treating with hydrofin- oric acid, however, a total decomposition is effected, and the protoxide of iron can then be determined In the diluted solution by hypermanganate of potassa. We have made a number of tests to prove that pure hydrofluoric acid (free from arsenic) does not affect the action of the standard potassic solution.. J. COOKE (Journal of Practical Uhemistry, vol. cii., page 456) has also shown that protoxide of iron in a solution of sulphate of iron may be accurately determined in the presence of hydrofluoric acid by hypermanganate of potassa. The specimens which were first subjected to analysis were two kinds of bricks from the works of Mr. OPPENHEThI, near Riidersdorf, and two others from the works of Dr. KUHNHEIM at Freienwalde on t~h~ Oder. The physical properties of these ma- terials and their total contents of iron were as fol- lows: RfiDERSDO1IF J3JtTcKs. No. 1. Pale red outside, more highly colored in- side; moderately hard; manufactured at cherry heat; contain 3.78 per cent of sesquioxide of iron. No. 2. Pale yellowish white, reddish inside; glazed, harder and firmer than No. 1 ; manufactured at a con- siderably higher temperature, verging on that of white heat; contain 4.26 per cent of ~esquioxide of iron. FREIENWALDE ]3lircKs. No. 8. Lively red; moderately hard and firm; manufactured at cherry heat; contains 3.79 per cent of sesquioxide of iron. No. 4. Darker red; more compact and of greater hardness than No. 3; manufactured at a temperature near white heat; contain 4.28 per cent of sesquiexide of iron. All these four specimens showed, during analyses, reactions so slight of protoxide of iron that its exist- ence, or trace even, is dubious. These facts show: 1st. That a relatively small percentage of peroxide of iron is sufficient to impart a lively red color to bricks. 2d. That with a perfectly equal percentage of iron, certain kinds of brick remain red when burned at nearly a white heat, whilst others turn pale without a reduction of their peroxide of iron into protoxide. The last difference is merely based upon a variation in the percentage of lime contained in the raw mate- rial. According to analyses made by Mr. HEY, at the laboratory of the Mining Academy at Berlin, under the supervision of Mr. FINKENEE, the clay of Steinitz- See, from which the Rildersdorf brick are made, con- tains 8.69 per cent, that of Freienxvalde only 2.47 per cent of lime, while the quantities of magnesia and alkalies are very minute and equal in both cases. The oxide of calcium, (lime,) if contained in consider- able quantity in the raw material, acts, under the in- fluence of high heat, upon the peroxide of iron, predis- posing it to enter the combination of a polybasic white silicate. It can not be supposed that a ferrate of lime is formed xvhile silicic acid is present in such decided excess. Besides, the pure compounds of this kind are reddish-brown. The magnesia, which exists mostly in insignificant quantities, does not seem to play an important part. According to the experience of many manufacturers, pale bricks are produced, especi- ally in those parts of the kiln where smoke has had a chance to collect or to touch the clay. The cause of this is the higher local temp~rature, resulting from a more intimate contact with combustible particles. If a brick containing but little lime changes in color from light red to dark red, an alteration only of the physical state of aggregation of the free uncom- blued peroxide of iron takes place; and this substance is the only cause of color in all kinds of brick. My. next communication will treat of green and dark-colored clinkers. How to Make Different Cements. A Cement withstanding Water, Acids, Oils, etc. Simple shellac, made up into sticks of the size of a lead pencil, is commonly sold for such cement. The objects to be cemented together are first warmed till they melt the shellac brought in contact with them. This is very good to cement broken glass, porcelain, etc., especially as the objects are again ready for use immediately when cold; but it is not adapted for flexible objects, as it cracks, and also will not with- stand heat or alcohol, which soften the shellac. A Cement withstanding Heat and AlcoholTake the best kind of glue; pour on an equal quantity of water; let it soak over night; next morning melt it over a gentle heat, and add fine Paris white, or white- lead; mix well, and add a little acetic acid, carbolic acid, oil of cloves, or any other ethereal oil, to prevent 3 putrefaction. This cement will also be adapted for flexible objects, like leather, and is sold at present from wagons in different cities of the United States. This cement xviii not withstand boiling water well, as this softens the glue. A Cement withstanding Heat and 3foisture 7joth. Simply pure white-lead, or zinc-white, ground in oil, andpsed very thick, is an excellent cement for mend- ing broken crockery ware; but it takes a very long time to harden sufficiently. The best plan is to place the mended object in some store-room, and not to look after it for several weeks, or even months.. After that time it will be found so firmly united that, if ever again broken, it will not part on the line of the former fracture. Learned Blacksmiths. Wuo has not heard of the learned blacksmith, En- RU BURRITE? His learning is, however, merely lite- rary and outside of his profession. In his youth little was known of that which at present con~titutes scien- tific, useful, and practical knowledge, and therefore it is not to be wondered at that a man in whom the natural thirst for information, which we observe in all children, has not been suppressed by defective educa- tion and bad company, satisfied this thirst by pure literary pursuits. At the present day it is different Scores of facts in natural science are known, studied, and applied; moi~e interesting, we think, than all the literary productions of Greece and Rome, together with those of some modern nations throxvn in; and a blacksmiths nowadays who wishes to extend the range of his knowledge need not go entirely outside of his occupation to satisfy his praiseworthy desires. An illustration of this was lately given in England, by Mr. SAXBY, xvho applied his knowledge of the pro- perties of magnets, the compass-needle, and the mysto-. rious magnetic properties of the e~trths to the detection of hidden defects in iron castings, wrought-iron shafts, and other heavy products of the iron industry. In order to understand this method, it must first be known that, xvhen a small magnetic steel bar is so supported or suspended by its centre of gravity that, besides being able to turn in a horizontal plane, it can also turn in sectional planes, it will not only point northward, but, at the same time; doxvnward, with an inclination of some seventy degrees. This downward inclination is called the dip of the needle; the end di- rected downward is called the north pole, the upper end the south pole. Secondly, it must be knoxvn that, if an elongated piece of iron is placed in the described position or nearly so, it xvihl become magnetic by the influence of the earths magnetism, and a common compass-needle will indicate this plainly. The loxver portion xviii obtain a so-called polarity, similar to the north pole of the compass-needle; the upper end one similar to the south pole. 1f however, this iron is placed in a horizontal position, pointing nearly east and west, but exactly perpendicular to the direction of this dipping-needle, it must lose this so-called magnetic polarity, especially if it is also thoroughly jarred by hammering. If, now, a compass-needle is passed along this bar, it must shoxv an equal attraction for the needle along its whole length. A flaw or bad place anywhere will be detected by an ir- regularity in the direction of the needle as it is passed over the spot. The inventor of this method xvas put to a severe test in England. In a heavy shaft of iron a large hole was drilled, filled up with an inferior iron, then plugged up, and turned off so smoothly that the place xvhere this had been done could not be detected. Mr. SAxEY found the place with his compass-needle, and stated that at this spot the strength of the shaft was not reliable. In every other case where he indi- cated hidden flaws in iron his statement was verified by subsequent examination. This is only one out of thousands of instances which might be brought forward indicating how the study of modern sciences possesses not only a peculiar charm unknown to those devoting themselves to mere lite- rary pursuits, but also bears practical fruits, beneficial /

The Manufacturer and Builder. teapot, so that any liquid poured in at the top will reach the bottom of the pot at once, without becoming diluted by the water. If sulphuric acid be now poured in slowly, a small quantity at a time, it xviii, as soon as it comes in contact with the chlorate of potash and phosphorus, cause a number of slight explosions, hiss, and make all kinds of noises, and give a literal illus- tration of the so-frequently mentioned phenomenon of a tempest in a teapot. Any glas-i ;c~zel may be sub- stituted for the teapot, and then the action of the chemicals may be observed. The Causes of the Difference in the Colorcf Bricks. A GREAT many erroneous Views exist among manu- facturers in regard to the chemical combinations to which the color of certain kinds of burnt bricks is to be ascribed. Especially strong is the belieg that white or light-colored bricks can only be produced un- der the influence of reducing processes, which would change the peroxide of iron into the protoxide ; al- though it is a well-known fact that the protoxide, in its combinations with other bases, forms a far greater xuiriety of more intensely colored compounds than the peroxide. If it were supposed that the metallic pro- toxide could remain in an uncombined state, a more or less black-colored mass would be the result. It has been surmised that sulphurous acid, resulting from pyritif~rous fuel, was an important agent in these sup- posed deoxidizing processes, although sulphurous acid can never play the part of a reducing agent in the high heat of a brick-kiln. The sulphuric acid, on the con- trary, which might have been contained in the clay, would, under these conditions, through the mere influ- ence of heat, be decomposed into suiphurons gas and free oxygen. On the other hand, it is maintained by some manufacturers that white bricks, which assume a green color when half-fused by high heat, owe this change of color and an increase of absolute weight to an addition of oxygen through the influence of protoxide of iron. In this case, as in the former, the reality of facts has been totally reversed; for, accord- ing to our investigations, the white bricks contain only peroxide of iron, and the green glazed ones, on the contrary, a considerable quantity of protoxide; the latter, thesefore, must have less absolute weight than when they were in the white state, and only the specific gravity of compact pieces has been increased, as, in consequence of a semi-fusion, most of their pores are closed. Some time since, we analyzed several bricks with reference to the above questions, and recently have given this subject renewed thought. The main ques- tion turns upon the determination of the quantity of iron present, and its state of oxidation; since this metal is not only the cause of the various tints, but even of the very existence of color in bricks. The most particular attention, therefore, had to be paid to the determination of the existence of protoxide of iron. This determination, however, presented some difficul- ties, since hard-burnt bricks are the most refractory of all complex silicious substances. Not even the color of pulverized bricks is materially changed by treatment with sulphuric acid, in a closed glass tube, according to Alex. Mitcherlichs method, at 35O~ centigrade, for eight to ten hours. By treating with hydrofin- oric acid, however, a total decomposition is effected, and the protoxide of iron can then be determined In the diluted solution by hypermanganate of potassa. We have made a number of tests to prove that pure hydrofluoric acid (free from arsenic) does not affect the action of the standard potassic solution.. J. COOKE (Journal of Practical Uhemistry, vol. cii., page 456) has also shown that protoxide of iron in a solution of sulphate of iron may be accurately determined in the presence of hydrofluoric acid by hypermanganate of potassa. The specimens which were first subjected to analysis were two kinds of bricks from the works of Mr. OPPENHEThI, near Riidersdorf, and two others from the works of Dr. KUHNHEIM at Freienwalde on t~h~ Oder. The physical properties of these ma- terials and their total contents of iron were as fol- lows: RfiDERSDO1IF J3JtTcKs. No. 1. Pale red outside, more highly colored in- side; moderately hard; manufactured at cherry heat; contain 3.78 per cent of sesquioxide of iron. No. 2. Pale yellowish white, reddish inside; glazed, harder and firmer than No. 1 ; manufactured at a con- siderably higher temperature, verging on that of white heat; contain 4.26 per cent of ~esquioxide of iron. FREIENWALDE ]3lircKs. No. 8. Lively red; moderately hard and firm; manufactured at cherry heat; contains 3.79 per cent of sesquioxide of iron. No. 4. Darker red; more compact and of greater hardness than No. 3; manufactured at a temperature near white heat; contain 4.28 per cent of sesquiexide of iron. All these four specimens showed, during analyses, reactions so slight of protoxide of iron that its exist- ence, or trace even, is dubious. These facts show: 1st. That a relatively small percentage of peroxide of iron is sufficient to impart a lively red color to bricks. 2d. That with a perfectly equal percentage of iron, certain kinds of brick remain red when burned at nearly a white heat, whilst others turn pale without a reduction of their peroxide of iron into protoxide. The last difference is merely based upon a variation in the percentage of lime contained in the raw mate- rial. According to analyses made by Mr. HEY, at the laboratory of the Mining Academy at Berlin, under the supervision of Mr. FINKENEE, the clay of Steinitz- See, from which the Rildersdorf brick are made, con- tains 8.69 per cent, that of Freienxvalde only 2.47 per cent of lime, while the quantities of magnesia and alkalies are very minute and equal in both cases. The oxide of calcium, (lime,) if contained in consider- able quantity in the raw material, acts, under the in- fluence of high heat, upon the peroxide of iron, predis- posing it to enter the combination of a polybasic white silicate. It can not be supposed that a ferrate of lime is formed xvhile silicic acid is present in such decided excess. Besides, the pure compounds of this kind are reddish-brown. The magnesia, which exists mostly in insignificant quantities, does not seem to play an important part. According to the experience of many manufacturers, pale bricks are produced, especi- ally in those parts of the kiln where smoke has had a chance to collect or to touch the clay. The cause of this is the higher local temp~rature, resulting from a more intimate contact with combustible particles. If a brick containing but little lime changes in color from light red to dark red, an alteration only of the physical state of aggregation of the free uncom- blued peroxide of iron takes place; and this substance is the only cause of color in all kinds of brick. My. next communication will treat of green and dark-colored clinkers. How to Make Different Cements. A Cement withstanding Water, Acids, Oils, etc. Simple shellac, made up into sticks of the size of a lead pencil, is commonly sold for such cement. The objects to be cemented together are first warmed till they melt the shellac brought in contact with them. This is very good to cement broken glass, porcelain, etc., especially as the objects are again ready for use immediately when cold; but it is not adapted for flexible objects, as it cracks, and also will not with- stand heat or alcohol, which soften the shellac. A Cement withstanding Heat and AlcoholTake the best kind of glue; pour on an equal quantity of water; let it soak over night; next morning melt it over a gentle heat, and add fine Paris white, or white- lead; mix well, and add a little acetic acid, carbolic acid, oil of cloves, or any other ethereal oil, to prevent 3 putrefaction. This cement will also be adapted for flexible objects, like leather, and is sold at present from wagons in different cities of the United States. This cement xviii not withstand boiling water well, as this softens the glue. A Cement withstanding Heat and 3foisture 7joth. Simply pure white-lead, or zinc-white, ground in oil, andpsed very thick, is an excellent cement for mend- ing broken crockery ware; but it takes a very long time to harden sufficiently. The best plan is to place the mended object in some store-room, and not to look after it for several weeks, or even months.. After that time it will be found so firmly united that, if ever again broken, it will not part on the line of the former fracture. Learned Blacksmiths. Wuo has not heard of the learned blacksmith, En- RU BURRITE? His learning is, however, merely lite- rary and outside of his profession. In his youth little was known of that which at present con~titutes scien- tific, useful, and practical knowledge, and therefore it is not to be wondered at that a man in whom the natural thirst for information, which we observe in all children, has not been suppressed by defective educa- tion and bad company, satisfied this thirst by pure literary pursuits. At the present day it is different Scores of facts in natural science are known, studied, and applied; moi~e interesting, we think, than all the literary productions of Greece and Rome, together with those of some modern nations throxvn in; and a blacksmiths nowadays who wishes to extend the range of his knowledge need not go entirely outside of his occupation to satisfy his praiseworthy desires. An illustration of this was lately given in England, by Mr. SAXBY, xvho applied his knowledge of the pro- perties of magnets, the compass-needle, and the mysto-. rious magnetic properties of the e~trths to the detection of hidden defects in iron castings, wrought-iron shafts, and other heavy products of the iron industry. In order to understand this method, it must first be known that, xvhen a small magnetic steel bar is so supported or suspended by its centre of gravity that, besides being able to turn in a horizontal plane, it can also turn in sectional planes, it will not only point northward, but, at the same time; doxvnward, with an inclination of some seventy degrees. This downward inclination is called the dip of the needle; the end di- rected downward is called the north pole, the upper end the south pole. Secondly, it must be knoxvn that, if an elongated piece of iron is placed in the described position or nearly so, it xvihl become magnetic by the influence of the earths magnetism, and a common compass-needle will indicate this plainly. The loxver portion xviii obtain a so-called polarity, similar to the north pole of the compass-needle; the upper end one similar to the south pole. 1f however, this iron is placed in a horizontal position, pointing nearly east and west, but exactly perpendicular to the direction of this dipping-needle, it must lose this so-called magnetic polarity, especially if it is also thoroughly jarred by hammering. If, now, a compass-needle is passed along this bar, it must shoxv an equal attraction for the needle along its whole length. A flaw or bad place anywhere will be detected by an ir- regularity in the direction of the needle as it is passed over the spot. The inventor of this method xvas put to a severe test in England. In a heavy shaft of iron a large hole was drilled, filled up with an inferior iron, then plugged up, and turned off so smoothly that the place xvhere this had been done could not be detected. Mr. SAxEY found the place with his compass-needle, and stated that at this spot the strength of the shaft was not reliable. In every other case where he indi- cated hidden flaws in iron his statement was verified by subsequent examination. This is only one out of thousands of instances which might be brought forward indicating how the study of modern sciences possesses not only a peculiar charm unknown to those devoting themselves to mere lite- rary pursuits, but also bears practical fruits, beneficial /

The Manufacturer and Builder. teapot, so that any liquid poured in at the top will reach the bottom of the pot at once, without becoming diluted by the water. If sulphuric acid be now poured in slowly, a small quantity at a time, it xviii, as soon as it comes in contact with the chlorate of potash and phosphorus, cause a number of slight explosions, hiss, and make all kinds of noises, and give a literal illus- tration of the so-frequently mentioned phenomenon of a tempest in a teapot. Any glas-i ;c~zel may be sub- stituted for the teapot, and then the action of the chemicals may be observed. The Causes of the Difference in the Colorcf Bricks. A GREAT many erroneous Views exist among manu- facturers in regard to the chemical combinations to which the color of certain kinds of burnt bricks is to be ascribed. Especially strong is the belieg that white or light-colored bricks can only be produced un- der the influence of reducing processes, which would change the peroxide of iron into the protoxide ; al- though it is a well-known fact that the protoxide, in its combinations with other bases, forms a far greater xuiriety of more intensely colored compounds than the peroxide. If it were supposed that the metallic pro- toxide could remain in an uncombined state, a more or less black-colored mass would be the result. It has been surmised that sulphurous acid, resulting from pyritif~rous fuel, was an important agent in these sup- posed deoxidizing processes, although sulphurous acid can never play the part of a reducing agent in the high heat of a brick-kiln. The sulphuric acid, on the con- trary, which might have been contained in the clay, would, under these conditions, through the mere influ- ence of heat, be decomposed into suiphurons gas and free oxygen. On the other hand, it is maintained by some manufacturers that white bricks, which assume a green color when half-fused by high heat, owe this change of color and an increase of absolute weight to an addition of oxygen through the influence of protoxide of iron. In this case, as in the former, the reality of facts has been totally reversed; for, accord- ing to our investigations, the white bricks contain only peroxide of iron, and the green glazed ones, on the contrary, a considerable quantity of protoxide; the latter, thesefore, must have less absolute weight than when they were in the white state, and only the specific gravity of compact pieces has been increased, as, in consequence of a semi-fusion, most of their pores are closed. Some time since, we analyzed several bricks with reference to the above questions, and recently have given this subject renewed thought. The main ques- tion turns upon the determination of the quantity of iron present, and its state of oxidation; since this metal is not only the cause of the various tints, but even of the very existence of color in bricks. The most particular attention, therefore, had to be paid to the determination of the existence of protoxide of iron. This determination, however, presented some difficul- ties, since hard-burnt bricks are the most refractory of all complex silicious substances. Not even the color of pulverized bricks is materially changed by treatment with sulphuric acid, in a closed glass tube, according to Alex. Mitcherlichs method, at 35O~ centigrade, for eight to ten hours. By treating with hydrofin- oric acid, however, a total decomposition is effected, and the protoxide of iron can then be determined In the diluted solution by hypermanganate of potassa. We have made a number of tests to prove that pure hydrofluoric acid (free from arsenic) does not affect the action of the standard potassic solution.. J. COOKE (Journal of Practical Uhemistry, vol. cii., page 456) has also shown that protoxide of iron in a solution of sulphate of iron may be accurately determined in the presence of hydrofluoric acid by hypermanganate of potassa. The specimens which were first subjected to analysis were two kinds of bricks from the works of Mr. OPPENHEThI, near Riidersdorf, and two others from the works of Dr. KUHNHEIM at Freienwalde on t~h~ Oder. The physical properties of these ma- terials and their total contents of iron were as fol- lows: RfiDERSDO1IF J3JtTcKs. No. 1. Pale red outside, more highly colored in- side; moderately hard; manufactured at cherry heat; contain 3.78 per cent of sesquioxide of iron. No. 2. Pale yellowish white, reddish inside; glazed, harder and firmer than No. 1 ; manufactured at a con- siderably higher temperature, verging on that of white heat; contain 4.26 per cent of ~esquioxide of iron. FREIENWALDE ]3lircKs. No. 8. Lively red; moderately hard and firm; manufactured at cherry heat; contains 3.79 per cent of sesquioxide of iron. No. 4. Darker red; more compact and of greater hardness than No. 3; manufactured at a temperature near white heat; contain 4.28 per cent of sesquiexide of iron. All these four specimens showed, during analyses, reactions so slight of protoxide of iron that its exist- ence, or trace even, is dubious. These facts show: 1st. That a relatively small percentage of peroxide of iron is sufficient to impart a lively red color to bricks. 2d. That with a perfectly equal percentage of iron, certain kinds of brick remain red when burned at nearly a white heat, whilst others turn pale without a reduction of their peroxide of iron into protoxide. The last difference is merely based upon a variation in the percentage of lime contained in the raw mate- rial. According to analyses made by Mr. HEY, at the laboratory of the Mining Academy at Berlin, under the supervision of Mr. FINKENEE, the clay of Steinitz- See, from which the Rildersdorf brick are made, con- tains 8.69 per cent, that of Freienxvalde only 2.47 per cent of lime, while the quantities of magnesia and alkalies are very minute and equal in both cases. The oxide of calcium, (lime,) if contained in consider- able quantity in the raw material, acts, under the in- fluence of high heat, upon the peroxide of iron, predis- posing it to enter the combination of a polybasic white silicate. It can not be supposed that a ferrate of lime is formed xvhile silicic acid is present in such decided excess. Besides, the pure compounds of this kind are reddish-brown. The magnesia, which exists mostly in insignificant quantities, does not seem to play an important part. According to the experience of many manufacturers, pale bricks are produced, especi- ally in those parts of the kiln where smoke has had a chance to collect or to touch the clay. The cause of this is the higher local temp~rature, resulting from a more intimate contact with combustible particles. If a brick containing but little lime changes in color from light red to dark red, an alteration only of the physical state of aggregation of the free uncom- blued peroxide of iron takes place; and this substance is the only cause of color in all kinds of brick. My. next communication will treat of green and dark-colored clinkers. How to Make Different Cements. A Cement withstanding Water, Acids, Oils, etc. Simple shellac, made up into sticks of the size of a lead pencil, is commonly sold for such cement. The objects to be cemented together are first warmed till they melt the shellac brought in contact with them. This is very good to cement broken glass, porcelain, etc., especially as the objects are again ready for use immediately when cold; but it is not adapted for flexible objects, as it cracks, and also will not with- stand heat or alcohol, which soften the shellac. A Cement withstanding Heat and AlcoholTake the best kind of glue; pour on an equal quantity of water; let it soak over night; next morning melt it over a gentle heat, and add fine Paris white, or white- lead; mix well, and add a little acetic acid, carbolic acid, oil of cloves, or any other ethereal oil, to prevent 3 putrefaction. This cement will also be adapted for flexible objects, like leather, and is sold at present from wagons in different cities of the United States. This cement xviii not withstand boiling water well, as this softens the glue. A Cement withstanding Heat and 3foisture 7joth. Simply pure white-lead, or zinc-white, ground in oil, andpsed very thick, is an excellent cement for mend- ing broken crockery ware; but it takes a very long time to harden sufficiently. The best plan is to place the mended object in some store-room, and not to look after it for several weeks, or even months.. After that time it will be found so firmly united that, if ever again broken, it will not part on the line of the former fracture. Learned Blacksmiths. Wuo has not heard of the learned blacksmith, En- RU BURRITE? His learning is, however, merely lite- rary and outside of his profession. In his youth little was known of that which at present con~titutes scien- tific, useful, and practical knowledge, and therefore it is not to be wondered at that a man in whom the natural thirst for information, which we observe in all children, has not been suppressed by defective educa- tion and bad company, satisfied this thirst by pure literary pursuits. At the present day it is different Scores of facts in natural science are known, studied, and applied; moi~e interesting, we think, than all the literary productions of Greece and Rome, together with those of some modern nations throxvn in; and a blacksmiths nowadays who wishes to extend the range of his knowledge need not go entirely outside of his occupation to satisfy his praiseworthy desires. An illustration of this was lately given in England, by Mr. SAXBY, xvho applied his knowledge of the pro- perties of magnets, the compass-needle, and the mysto-. rious magnetic properties of the e~trths to the detection of hidden defects in iron castings, wrought-iron shafts, and other heavy products of the iron industry. In order to understand this method, it must first be known that, xvhen a small magnetic steel bar is so supported or suspended by its centre of gravity that, besides being able to turn in a horizontal plane, it can also turn in sectional planes, it will not only point northward, but, at the same time; doxvnward, with an inclination of some seventy degrees. This downward inclination is called the dip of the needle; the end di- rected downward is called the north pole, the upper end the south pole. Secondly, it must be knoxvn that, if an elongated piece of iron is placed in the described position or nearly so, it xvihl become magnetic by the influence of the earths magnetism, and a common compass-needle will indicate this plainly. The loxver portion xviii obtain a so-called polarity, similar to the north pole of the compass-needle; the upper end one similar to the south pole. 1f however, this iron is placed in a horizontal position, pointing nearly east and west, but exactly perpendicular to the direction of this dipping-needle, it must lose this so-called magnetic polarity, especially if it is also thoroughly jarred by hammering. If, now, a compass-needle is passed along this bar, it must shoxv an equal attraction for the needle along its whole length. A flaw or bad place anywhere will be detected by an ir- regularity in the direction of the needle as it is passed over the spot. The inventor of this method xvas put to a severe test in England. In a heavy shaft of iron a large hole was drilled, filled up with an inferior iron, then plugged up, and turned off so smoothly that the place xvhere this had been done could not be detected. Mr. SAxEY found the place with his compass-needle, and stated that at this spot the strength of the shaft was not reliable. In every other case where he indi- cated hidden flaws in iron his statement was verified by subsequent examination. This is only one out of thousands of instances which might be brought forward indicating how the study of modern sciences possesses not only a peculiar charm unknown to those devoting themselves to mere lite- rary pursuits, but also bears practical fruits, beneficial / 4 not only to the possessor, but also to human society in general, and showing themselves in the saving of life, the promotion of health, the increase of wealth a ndcomfort, and so forth. DoveTail Joints. Tnu strongest and most permanent joint made in carpentry and cabinet-making, where pieces of wood are fastened together at right angles, is the dove-tail. When made in some of its .most approved and perfect- ed forms, it is equal, in neatness and artistic finish to the mitre joint; The mitre is a comparatively neater method of joining wood at an angle, but the dove-tail possesses the greatest possible strength. It is gene- rally employed in articles made of thin materials, such, for instance, as drawers, boxes, chests, etc. If we examine a dove-tailed box, we observe that it consists of six pieces, or sides, four of which are interlaced, or dove-tailed together at the corners, forming a rigid frame-work. This is shown in Fig. 1. When properly put together, the joint formed by the two pieces A and B is strengthened and braced by those of C and D. The rigidity of the box is of course still further in- creased by attaching the bottom, which may be done by means of screws, or glue and screws may be both employed. There is an advantage in the employment of the latter, for if the dove-tails should be somewhat loosely fitted, or the glue lose it .adhesive power, the screws will prevent any disposition of the four sides to rack. When we wish to have the lid of con- siderable depth, and fastened together by dove-tails, the box is made sufficiently deep to form both box and cover. The top and bottom pieces are then added. The six pieces so joined have the appearance of a rect- angular block or cube. A saw is employed to sepa. rate the cover, or lid, from the bottom portion. This method has the advantage of saving some labor in dove-tailing. It insures the exact agreement in size and form of box and cover. It would be somewhat difficult to effect this were they separately made. This would especially be the case in making such articles as desks and writing-cases. In all boxes where the bottom and lid are made together, the line of division is marked on the four exterior sides. One of the dove-tail pins is placed on that line. This pin should be aboUt twice as wide as the others. When divided in forming the cover, either part is then of the size of the others. In order to have the cover and box show a mitre joint, the dove-tail and joint pin are made to a mitre; whereas, if the pin were left square, or made as usual, the box when cut open would show the rectangular lines of the pin and dove-tail. - The top and bottom of the box may be fitted in various ways. They may be glued, or otherwise fastened, on the square edges of its sides. They may be rebated; or, to cause a more finished appearance, they may be both rebated and mitred. In Fig. 2, the common dove-tail joint is shown, in which the dove-tails and pins are seen upon both sides; When the gr~Un of the wood of the parts joined together runs in the same direction, such parts will expand and contract equally, should they be equally moist and dry. This expansion or contrac- tion can then take place without injury to the work. In order to effect this, it is advisable to niake the work from the same board, or from pieces of boards of The Manufacturer and Builder. the same quality of timber, and having come as near as may be from the same relative position in the logs from which they were sawn. This can be very readily ascertained by an examination of the ends of the pieces, the curvature or configuration of the grain fur. nishing the desired information. If the pieces of work have the grain running in contrary directions, as seen in Fig. 3, it is evident that the portion D would en- tirely prevent the expansion of C, and the restraint would cause injury to the joint. This would be the inevitable result in case of much expansion or shrink- age. In order to explain this more fully, let Fig. 4 represent the surface of a board, its edge being in- dicated by a b, and the end by c d. It is evident that no contraction can occur in the direction of the line a b, which is that of the grain of the wood. Along this line the wood-fibres remain quite rigId, the shrinkage taking place in the direction of the line c d. The flexible fibres are in this direction, and more or less disposed to become curved from ex- posure to the atmosphere. The four marginal lines of the board are not likely to change very materially in respect to each other, and if made parallel and square at first will remain so. F~o 4. d C Fig. 5 represents the ordinary dove-tail joint. Fig. 6 shows the parts before they are put together. The pins are shown at P, and the dove-tails at C. The pins and dove-tails are commonly made of about- the same size, as this gives the strongest kind of attach- ) meat; but in many forms of cabinet-work the dove. tails are made on the front, or more exposed por- tion, and the pins are cut about one fourth less ~in size than the dove-tails, in order that as little as pos- sible of the end wood may be seen. In laying out dove-tails, the sides and ends of the boards are first marked across with a gauge or square, to indicate the inside measure of the box or drawer, and also the bot- tom of the pins and dove-tails. The portions beyond the lines are left a little longer than ultimately re- quired. In laying out the pins very little care is required. It is a common practice to mark them off at random. Care must be taken to leave the outside pins nearly twice as large as the inside ones. The dove-tails are then marked from the pins; they thus become exact counterparts of each other. The piece upon which the pins are made is laid upon the work- bench, and that upon which the dove-tails are to be made is held vertically upon it in the exact position FicG, that the two pieces are to occupy. A fine point or pen- cil is then used to mark the outline of each pin. This being done, a fine saw may be used for both pin and and dove-tail, taking care that it follows the outlines and does not cut below the gauge mark that limits the interior of the work. By not cutting into the outline marks, both pins and dove-tails will be a trifle too large, and in driving them together they will coin- press each other a little, and produce a close and accu- rate joint. After cutting with a saw to the depth required for the pins and dove-tails, a sharp chisel is used to remove the wood that remains between the portions that are to b6 retained. A ready method of doing this is to lay the several pieces one upon another, similar to a flight of stairs, and cut half way through them successively, and then turn them over, arrange them as before, and cut the other side, which operation removes the pieces. This method enables a mechanic to work with celerity, and also permits him to see what he is doing. The chisel should be held so that the cut will extend inward at the base of the pins and dove-tails, meeting at the centre of the board. This will insure a tight-fitting joint when the work is put liogether. It is advisable not to make the pins and dove-tails with any considerable degree of bevel, or the connec- tion will be deficient in strength. When pine or soft, brittle wood is employed, the parts should be slightly beveled; but more bevel should be allowed to hard wood, such as oak or mahogany. In making the out- lines of the work upon some hard woodsmahogany, for instanceit is difficult to observe the lines; but if the surface of the wood be rubbed with chalk before marking, the lines will be rendered conspicuous. In gluing the dove-tails of a box, as seen in Fig. 1, it is best that the pins on the side A be first sparingly glued, and held by some sort of fixture in a vertical position, with the glued end uppermost. The end B, which is to be attached, is held horizontally, and forced down upon A. This is conveniently done by blows of a mallet or hammer, which, to prevent injury to the work, are received upon a piece of waste wood placed directly over the pins. When the pins come flush with the upper face of the board B, the piece of waste wood is placed beside them, so as to allow the pins to rise above the surface. It is essential that the pins and dove-tails should exceed the thicknes~ of the board, so that when the superfluous length is planed P C

4 not only to the possessor, but also to human society in general, and showing themselves in the saving of life, the promotion of health, the increase of wealth a ndcomfort, and so forth. DoveTail Joints. Tnu strongest and most permanent joint made in carpentry and cabinet-making, where pieces of wood are fastened together at right angles, is the dove-tail. When made in some of its .most approved and perfect- ed forms, it is equal, in neatness and artistic finish to the mitre joint; The mitre is a comparatively neater method of joining wood at an angle, but the dove-tail possesses the greatest possible strength. It is gene- rally employed in articles made of thin materials, such, for instance, as drawers, boxes, chests, etc. If we examine a dove-tailed box, we observe that it consists of six pieces, or sides, four of which are interlaced, or dove-tailed together at the corners, forming a rigid frame-work. This is shown in Fig. 1. When properly put together, the joint formed by the two pieces A and B is strengthened and braced by those of C and D. The rigidity of the box is of course still further in- creased by attaching the bottom, which may be done by means of screws, or glue and screws may be both employed. There is an advantage in the employment of the latter, for if the dove-tails should be somewhat loosely fitted, or the glue lose it .adhesive power, the screws will prevent any disposition of the four sides to rack. When we wish to have the lid of con- siderable depth, and fastened together by dove-tails, the box is made sufficiently deep to form both box and cover. The top and bottom pieces are then added. The six pieces so joined have the appearance of a rect- angular block or cube. A saw is employed to sepa. rate the cover, or lid, from the bottom portion. This method has the advantage of saving some labor in dove-tailing. It insures the exact agreement in size and form of box and cover. It would be somewhat difficult to effect this were they separately made. This would especially be the case in making such articles as desks and writing-cases. In all boxes where the bottom and lid are made together, the line of division is marked on the four exterior sides. One of the dove-tail pins is placed on that line. This pin should be aboUt twice as wide as the others. When divided in forming the cover, either part is then of the size of the others. In order to have the cover and box show a mitre joint, the dove-tail and joint pin are made to a mitre; whereas, if the pin were left square, or made as usual, the box when cut open would show the rectangular lines of the pin and dove-tail. - The top and bottom of the box may be fitted in various ways. They may be glued, or otherwise fastened, on the square edges of its sides. They may be rebated; or, to cause a more finished appearance, they may be both rebated and mitred. In Fig. 2, the common dove-tail joint is shown, in which the dove-tails and pins are seen upon both sides; When the gr~Un of the wood of the parts joined together runs in the same direction, such parts will expand and contract equally, should they be equally moist and dry. This expansion or contrac- tion can then take place without injury to the work. In order to effect this, it is advisable to niake the work from the same board, or from pieces of boards of The Manufacturer and Builder. the same quality of timber, and having come as near as may be from the same relative position in the logs from which they were sawn. This can be very readily ascertained by an examination of the ends of the pieces, the curvature or configuration of the grain fur. nishing the desired information. If the pieces of work have the grain running in contrary directions, as seen in Fig. 3, it is evident that the portion D would en- tirely prevent the expansion of C, and the restraint would cause injury to the joint. This would be the inevitable result in case of much expansion or shrink- age. In order to explain this more fully, let Fig. 4 represent the surface of a board, its edge being in- dicated by a b, and the end by c d. It is evident that no contraction can occur in the direction of the line a b, which is that of the grain of the wood. Along this line the wood-fibres remain quite rigId, the shrinkage taking place in the direction of the line c d. The flexible fibres are in this direction, and more or less disposed to become curved from ex- posure to the atmosphere. The four marginal lines of the board are not likely to change very materially in respect to each other, and if made parallel and square at first will remain so. F~o 4. d C Fig. 5 represents the ordinary dove-tail joint. Fig. 6 shows the parts before they are put together. The pins are shown at P, and the dove-tails at C. The pins and dove-tails are commonly made of about- the same size, as this gives the strongest kind of attach- ) meat; but in many forms of cabinet-work the dove. tails are made on the front, or more exposed por- tion, and the pins are cut about one fourth less ~in size than the dove-tails, in order that as little as pos- sible of the end wood may be seen. In laying out dove-tails, the sides and ends of the boards are first marked across with a gauge or square, to indicate the inside measure of the box or drawer, and also the bot- tom of the pins and dove-tails. The portions beyond the lines are left a little longer than ultimately re- quired. In laying out the pins very little care is required. It is a common practice to mark them off at random. Care must be taken to leave the outside pins nearly twice as large as the inside ones. The dove-tails are then marked from the pins; they thus become exact counterparts of each other. The piece upon which the pins are made is laid upon the work- bench, and that upon which the dove-tails are to be made is held vertically upon it in the exact position FicG, that the two pieces are to occupy. A fine point or pen- cil is then used to mark the outline of each pin. This being done, a fine saw may be used for both pin and and dove-tail, taking care that it follows the outlines and does not cut below the gauge mark that limits the interior of the work. By not cutting into the outline marks, both pins and dove-tails will be a trifle too large, and in driving them together they will coin- press each other a little, and produce a close and accu- rate joint. After cutting with a saw to the depth required for the pins and dove-tails, a sharp chisel is used to remove the wood that remains between the portions that are to b6 retained. A ready method of doing this is to lay the several pieces one upon another, similar to a flight of stairs, and cut half way through them successively, and then turn them over, arrange them as before, and cut the other side, which operation removes the pieces. This method enables a mechanic to work with celerity, and also permits him to see what he is doing. The chisel should be held so that the cut will extend inward at the base of the pins and dove-tails, meeting at the centre of the board. This will insure a tight-fitting joint when the work is put liogether. It is advisable not to make the pins and dove-tails with any considerable degree of bevel, or the connec- tion will be deficient in strength. When pine or soft, brittle wood is employed, the parts should be slightly beveled; but more bevel should be allowed to hard wood, such as oak or mahogany. In making the out- lines of the work upon some hard woodsmahogany, for instanceit is difficult to observe the lines; but if the surface of the wood be rubbed with chalk before marking, the lines will be rendered conspicuous. In gluing the dove-tails of a box, as seen in Fig. 1, it is best that the pins on the side A be first sparingly glued, and held by some sort of fixture in a vertical position, with the glued end uppermost. The end B, which is to be attached, is held horizontally, and forced down upon A. This is conveniently done by blows of a mallet or hammer, which, to prevent injury to the work, are received upon a piece of waste wood placed directly over the pins. When the pins come flush with the upper face of the board B, the piece of waste wood is placed beside them, so as to allow the pins to rise above the surface. It is essential that the pins and dove-tails should exceed the thicknes~ of the board, so that when the superfluous length is planed P C The Manufacturer and Builder. off, a good, clear joint is apparent. The second side, C, is then glued, similar to A, and held in the same manner, and B is forced down upon it. The three sides of the box are thus united. The pins upon the other ends of A and C are then glued; the end B is placed face downward upon the bench or floor, rest- ing upon two smooth strips of wood, placed close beside the projecting pins. Care should be taken to have it rest firmly. The remaining side, D, is then driven down upon it, and the four sides of the box united. The su- perfluous glue, forced out by the crowding together of the parts, .is then scraped off, while yet soft, with a chisel; but, where moisture will not affect the work, the remaining portions of the glue may be washed off with a sponge, wet with hot water from th~ glue kettle. Where it can be safely applied, this is the best method, as every vestige of the glue is removed from the surface of the work. To ascertain if the box has become rhomboidal, or, as it is technically termed, out of square, it can be tested with the fitting square, and it should be im- mediately corrected before the glue becomes set, or dry. This correction can be made by pressure ap- plied to the longer diagonal. A ready means of ascer- taining any deviation from a square is to find the exact distance that should exist between diagonals, and then to cut a thin strip of wood of just this length, and so sharpen the ends that they will be more acute than the angles of the box. It will exactly fill the space between the diagonal ~lines if the angles are correctthat is, if they are exactly ninety degrecs. In some kinds of dove-tails the pins are more or less concealed. Fig. 7 shows a form called the lap dove- tail, which is generally employed for the fronts of drawers. Fig. 8 shows the manner of attachment. The pins are on the front of the drawer, and are first made. Gauge lines are marked to denote how far the pins shall extend inward. It. will be observed that neither pins nor dove-tails extend quite through the wood in which they are respectively formed; hence the concealment of their end grain. It is, however, immaterial in which piece the pins or dove-tails are made. The depth of the latter is generally about one eighth of an inch less than the thickness of the piece containing them, and the pins are of a corresponding length. If the ends of the pins were made even with the end of the wood,.they would reach the bottom of the dove-tails, and an open corner would .be the result. The pins are generally cut back one eighth of an inch from the front end; otherwise the amount of the dove-tails would be shallower tban the thickness of the piece in which they are made. In drawers, the side~ are about half the thickness of the front; the dove-tails are, therefore, cut quite through them, the same as.in the oiAinary dove-tail, shown in Fig. 5. If the front part of tl~e drawer is to be covered with veneer, the pins are cut quite through with a saw, the kerfs being entirely concealed when the veneer is applied. Fig. 9 shows the mitre dove-tail joint, and Fig. 10 represents its construction. This is the neatest and the most difficult to make. The pieces must be cut to the external dimensions of the work, and then re- bated out square at each end; and after the pins and dove-tails have been formed, the square rebates are cut into a mitre joint, a rebate plane being used for the purpose. When properly finished, neither th~ pins nor their mode of concealment can be seen, and the work has the appearance of a plain mitre joint. As in the mitre, this rebate should have an angle of forty-five degrees. Fic IL In Fig. 11 is seen another form of finish sometimes given to the lap dove-tail, shown in Fig. 7. When the two pieces are put together, they resemble the form seen in Fig. 12, and the final finish is given by Fic 12. simply rounding the corner, removing the angular projections, until it assumes the appearance seen in Fig. 11. Boxes are often made by rebating one side or piece, the end of the other being received into this rebate, and then glued and nailed. The successiVe operations present the appearances shown in the cuts. It is quite a quick and cheap method of joining, and, when nailed from both angles, is, next in strength to the dove-tail. Fig. 13 is a simple and strong fastening, somewhat resembling the exterior appearance of the mitre dove~ - tail joint. It is termed the mitre and keyed joint. Small boxes, and similar light articles that do not re- quire much strength, and where cheapness of mann- Fic I3~ facture is desirable, are thus made. The extremities of the end and side pieces are mitred or planed to an angle of forty-five degrees, and attached by glue or suitable nails. A few upward and downward cuts are then made with a saw, and pieces of veneer or thin wood, covered with glue, drawn into them and al- lowed to dry. These pieces ~re then cut off flush with the sides of the work. If properly done, the ends and sides will form aiigles of ninety degrees with each other, or, in other words, the box will he exactly square. Wall-Dam p. IN laying the foundation of any building, the matter of particular consideration should be the thorough drain- age of the site, and next to that complete prevention of wall-dampthat is, the rising of moisture, by capil- lary attraction, or otherwise, in the heart of the brick or stone-work. Cement is used in the joints and tem- plars laid to effect this purpose, and it does, to a certain extent; but it is absolutely necessary that it should be a perfect prevention. Now it is not; for wherever brick-work comes in contact with the earth or even with adjacent walls which may happen to be damp, there the infection is certain to take, and there is no cure for it if once it makes an entrance. The readiest remedy in all cases is a layer of fine concrete, thinly coated on the top with asphaltum laid on hot. This done all around the top of the walls, ex- ternal and internal, the piers, and every piece of brick- work that in any manner has connection with the ground, then the bricks forming the next course should be heated over charcoal furnaces, and their beds dipped in the asphaltum before being laid. It is evident that a preventive course could thus be formed above ground at a trifling expense, wholly impervious to wall-damp, and, at the same time, giving a bedding to the superstructure of a quality very far superior to any now in use. Hollow walls have often been urged as a complete defense against wall-damp; but it stands to reason that they can not be; for there must be bind- ers between the outer and the inner wall section; and these very binders, sufficiently numerous too, must of themselves produce the effect we are concerned to avoid. Moreover, hollow walls, hollow bricks, and all such devices are productive of weakness, unless the work is made thicker, in which case they are produc- tive of extra expense. Coating the outside face of the walling with water- proof cement, or compo, is only to increase the facility for the action of capillary attraction from below, by excluding the external air and letting the artificial heat of the rooms attract the enemy. Brick will absorb fully one fifth of its weight of water, and where the storm drives the rain continu- ously against the face of a wall for a sufficient time to permit the interior heat to attract it, the inside of the wall must of necessity be damp, and the papering be- come mouldy, as well as the ceiling next it rotten. Limestone has a propensity to sweat, and in this way becomes, if not furred, very wet on the inside, un- less, indeed, the outside be coated with stucco, thus rendering such walls rather expensive. FIQ 9. F~G7.

The Manufacturer and Builder. off, a good, clear joint is apparent. The second side, C, is then glued, similar to A, and held in the same manner, and B is forced down upon it. The three sides of the box are thus united. The pins upon the other ends of A and C are then glued; the end B is placed face downward upon the bench or floor, rest- ing upon two smooth strips of wood, placed close beside the projecting pins. Care should be taken to have it rest firmly. The remaining side, D, is then driven down upon it, and the four sides of the box united. The su- perfluous glue, forced out by the crowding together of the parts, .is then scraped off, while yet soft, with a chisel; but, where moisture will not affect the work, the remaining portions of the glue may be washed off with a sponge, wet with hot water from th~ glue kettle. Where it can be safely applied, this is the best method, as every vestige of the glue is removed from the surface of the work. To ascertain if the box has become rhomboidal, or, as it is technically termed, out of square, it can be tested with the fitting square, and it should be im- mediately corrected before the glue becomes set, or dry. This correction can be made by pressure ap- plied to the longer diagonal. A ready means of ascer- taining any deviation from a square is to find the exact distance that should exist between diagonals, and then to cut a thin strip of wood of just this length, and so sharpen the ends that they will be more acute than the angles of the box. It will exactly fill the space between the diagonal ~lines if the angles are correctthat is, if they are exactly ninety degrecs. In some kinds of dove-tails the pins are more or less concealed. Fig. 7 shows a form called the lap dove- tail, which is generally employed for the fronts of drawers. Fig. 8 shows the manner of attachment. The pins are on the front of the drawer, and are first made. Gauge lines are marked to denote how far the pins shall extend inward. It. will be observed that neither pins nor dove-tails extend quite through the wood in which they are respectively formed; hence the concealment of their end grain. It is, however, immaterial in which piece the pins or dove-tails are made. The depth of the latter is generally about one eighth of an inch less than the thickness of the piece containing them, and the pins are of a corresponding length. If the ends of the pins were made even with the end of the wood,.they would reach the bottom of the dove-tails, and an open corner would .be the result. The pins are generally cut back one eighth of an inch from the front end; otherwise the amount of the dove-tails would be shallower tban the thickness of the piece in which they are made. In drawers, the side~ are about half the thickness of the front; the dove-tails are, therefore, cut quite through them, the same as.in the oiAinary dove-tail, shown in Fig. 5. If the front part of tl~e drawer is to be covered with veneer, the pins are cut quite through with a saw, the kerfs being entirely concealed when the veneer is applied. Fig. 9 shows the mitre dove-tail joint, and Fig. 10 represents its construction. This is the neatest and the most difficult to make. The pieces must be cut to the external dimensions of the work, and then re- bated out square at each end; and after the pins and dove-tails have been formed, the square rebates are cut into a mitre joint, a rebate plane being used for the purpose. When properly finished, neither th~ pins nor their mode of concealment can be seen, and the work has the appearance of a plain mitre joint. As in the mitre, this rebate should have an angle of forty-five degrees. Fic IL In Fig. 11 is seen another form of finish sometimes given to the lap dove-tail, shown in Fig. 7. When the two pieces are put together, they resemble the form seen in Fig. 12, and the final finish is given by Fic 12. simply rounding the corner, removing the angular projections, until it assumes the appearance seen in Fig. 11. Boxes are often made by rebating one side or piece, the end of the other being received into this rebate, and then glued and nailed. The successiVe operations present the appearances shown in the cuts. It is quite a quick and cheap method of joining, and, when nailed from both angles, is, next in strength to the dove-tail. Fig. 13 is a simple and strong fastening, somewhat resembling the exterior appearance of the mitre dove~ - tail joint. It is termed the mitre and keyed joint. Small boxes, and similar light articles that do not re- quire much strength, and where cheapness of mann- Fic I3~ facture is desirable, are thus made. The extremities of the end and side pieces are mitred or planed to an angle of forty-five degrees, and attached by glue or suitable nails. A few upward and downward cuts are then made with a saw, and pieces of veneer or thin wood, covered with glue, drawn into them and al- lowed to dry. These pieces ~re then cut off flush with the sides of the work. If properly done, the ends and sides will form aiigles of ninety degrees with each other, or, in other words, the box will he exactly square. Wall-Dam p. IN laying the foundation of any building, the matter of particular consideration should be the thorough drain- age of the site, and next to that complete prevention of wall-dampthat is, the rising of moisture, by capil- lary attraction, or otherwise, in the heart of the brick or stone-work. Cement is used in the joints and tem- plars laid to effect this purpose, and it does, to a certain extent; but it is absolutely necessary that it should be a perfect prevention. Now it is not; for wherever brick-work comes in contact with the earth or even with adjacent walls which may happen to be damp, there the infection is certain to take, and there is no cure for it if once it makes an entrance. The readiest remedy in all cases is a layer of fine concrete, thinly coated on the top with asphaltum laid on hot. This done all around the top of the walls, ex- ternal and internal, the piers, and every piece of brick- work that in any manner has connection with the ground, then the bricks forming the next course should be heated over charcoal furnaces, and their beds dipped in the asphaltum before being laid. It is evident that a preventive course could thus be formed above ground at a trifling expense, wholly impervious to wall-damp, and, at the same time, giving a bedding to the superstructure of a quality very far superior to any now in use. Hollow walls have often been urged as a complete defense against wall-damp; but it stands to reason that they can not be; for there must be bind- ers between the outer and the inner wall section; and these very binders, sufficiently numerous too, must of themselves produce the effect we are concerned to avoid. Moreover, hollow walls, hollow bricks, and all such devices are productive of weakness, unless the work is made thicker, in which case they are produc- tive of extra expense. Coating the outside face of the walling with water- proof cement, or compo, is only to increase the facility for the action of capillary attraction from below, by excluding the external air and letting the artificial heat of the rooms attract the enemy. Brick will absorb fully one fifth of its weight of water, and where the storm drives the rain continu- ously against the face of a wall for a sufficient time to permit the interior heat to attract it, the inside of the wall must of necessity be damp, and the papering be- come mouldy, as well as the ceiling next it rotten. Limestone has a propensity to sweat, and in this way becomes, if not furred, very wet on the inside, un- less, indeed, the outside be coated with stucco, thus rendering such walls rather expensive. FIQ 9. F~G7. The Manufacturer and Builder. Painting the brick-work in positions is efficacious, bat has to be repeated, and; in the end, apt to make brick-work little, if any, cheaper than brown stone. in all these cases we are supposing the locality of the ~vork to be very exposed, as nrc a great many valuable residences. Of course, wooden structures are free from this annoyance; but the more substantial materials are now taking the lead of the t~e.-honored and once cherished frame, and so we must consider all the try- Ing necessities of location for brick, as being the most generally used of all materials for walls. Where the case is a trying one, slating the face of the wall ~vill be found a good practice, and ma~ be made very orna- mental by cutting off the lower ai~gles of each slate, in belts, ned by staining in different colors, as is done frequently -on Mansard roofs. The wall to be slated should first be furred in horizontal courses, and the weather or exposed face of the slate should be ei~ht inches, and not more. The furring pieces should be very well secured throughout, and be not less than three inches broad by one inch thick. The slates should be secured with copper nails, two at the shoul- ders and one at the tail. This cause of wall-damp is one that can not be too carefully guarded against, as it is one to which may be referred the early decay of many residences, as well as the inception of those pulmonary symptoms which so surely steal away the health, and ultimately the life, of many a victim. Persons building villas and bathing-lodges on the sea-shore should be cautious that sea-sand be not used in the mortar, as the presence of such material is cer- tain to create the damp by absorbing all the water in the atmosphere, this being the chemical effect of its saline property. With respect to the surface of walls of rooms, it may l)e as well to remark here that there are two ways of coating them besides wainscotingnamely, papering and painting. The former is objectionable, inasmuch as it is as porous as the plaster face it is intended to pro- tect; and when a room is uninhabited and unheated for a time, the natural damp of the atmosphere will be absorbed by the paper and lodge in the plaster, until the first lighting of a fire in the apartment draws it by degrees from its retreat. This process of exhala- tion must affect the durability of the wood-work, as well as the plastering of such rooms, not to speak of the torments of rheumatism to which poor humanity is rendered liable. As regards painting, its disadvan- tage in comparison with papering lies in its greater cost at first. In the question of duration as well as utility, it is the cheaper. The process of painting plaster-work is as fellows White-lead and linseed oil, with a little litharge to facilitate the drying, are mixed together to about the consistency of thin cream; a coating of this being ap- plied, the oil from it is sucked into the plaster in a few houis, leaving the white lead apparently dry upon the surface. Ia the course of a day or two, when this coat has sufficiently hardened, another is given a few de- grees thicker, the oil from which is partially absorbed, according to the nature of the plaster. This coat is made pretty thick, and if the absorption of the oil from the second coat has not been great, about one fou4h of spirits of turpentine is added; but where the absorption has been great, a iC55 propoition of spirits of turpentine is used. Into this coat the color- ing ingredients may be put which are to bring it near the shade of the finishing coat. Should the plaster now be thoroughly saturated, the flatting or finishing coat is applied. Before this is done, however, a fourth coat, thinned with equal proportioiis of oil and spirits of turpentine, is generally given, particularly where the work is wished to be of the most durable kind. The flatting or finishing coat is composed entirely of paintthat is, of white lead and the coloring ingre- dients, mixed together and ground in oil to an impalpable paste. This mixture is Qf .a very thick consistency, and must be thinned with spirits of tur- pentine until it will flow easily from the brush. The spirits of twpei~tine, being very volatile, evaporate entirely, leaving the surface of the paint of a very compact and hard nature. By this process the plaster is rendered incapable of absorption, and the, surface of it is hardened by the oil which it has sucked in from the first and second coats, and is thereby rendered less liable to breakage, with the great advantage of being washable. In another number of THE MANUFAcTURER AND BUILDER we will discuss the relative merits of some proposed coverings for Rails, with some suggestions of our own. The Utilization of Tin Scraps. I. UTILIZATION OF THE TIN. 1. Preparation of the Stannate of SodaFor the preparation of this product, which is largely used as a mordant in dyeing, the tin scraps are rolled up into spirals and placed in a wooden tank. For every one hundred pounds, ten pounds of sulphur and five pounds of caustic soda are added. The whole is then covered with water and steam turned on. By the chemical action which ensties, the scraps will very soon be freed from the tin, the blank iron making its appearance; The liquid is then drawn off, filtered, and evaporated, until a thin skin appears on the sur- face, when it is left to cool. Crystals of Glauber salt, which is a secondary product in this process, will ap- pear on the sides of the vessel; these are separated, and the remaining liquid is again filtered and evapo- rated to dryness. The hard cake obtained constitutes the stannate of soda, or Praeparirscdz., as it is called by the Germans. From one hundred pounds of scraps twelve to fifteen pounds of this salt are obtained, worth from 18 to 20 cents a pound. 2. Preparation of a new non-poisonous Green Paint. This new paint, which we propose to call Phanician Green, (because tin, one of its constituents, was first known among the Ph~nicians,) is cheap, does not fade, darkens with oil, and may be used as lime-and- water-color. It is made by mixing a solution of fifteen parts soda stannate with twelve parts blue copperas, the former being added to the latter. The precipitate obtained is brought up on a filter, well washed out, and dried. By mixitug it with a decoction of yellow- woo(l, or seine chrome-yellow, its color may be changed more into blue. - 3. Pin/c Uolor.-T his may also be applied as a paint, but it is of more value in the decoration of porcelain and Falence ware. It is similar to the red of the madder, and is prepared by mixing intimately three partsstannic acid with four parts chalk, two parts fine quartz sand, and one tenth part of bichromate of potassa, and ox-- posing the resulting mass in a 1-lessian crucible to white heat. The product obtained is finely powdered, washed out with water, and dried. The stannic acid is obtained by treating the tin scraps with aqua fortis, collecting the resulting white powder, and heating the same in the air. - 4. Yellow Bronze for WoodFirst, we prepare me tahhic tin by .inserting tin scraps in muriatic acid, which is placed in a glazed pot. When tIne tin is dis- solved, the liquid is transferred into another vessel, and new strips are inserted, this process being repeated till the liquid is saturated. After this, copper plates are hung in the same, on which, by galvanic action, tine tin will be precipitated as a spongy mass. The result- ing chloride of copper may be used iRstead of the bl~ie copperas in the preparation of the Phmnician green. The spongy mass is-washed out, dried, and mixed with equal parts of sulphur and sal ammoniac. The mixture is put in a glass retort and heated in a sand-bath, when the yellow bronze is obtained as a sublimate. - II. UTILIZATION OF THE IRON. ~. Prepceration of c Polishing Powder fom Glasses. The product to start with for the m~king of this excel- lent article is the green copperas, which is obtained by the oombination of oil of vitriol with iron. A solu- tion of the copperas, when treated with oxalic acid, will yield the powder, which only needs to be dried and exposed to heat. 6. Preparation of Iron GreenThis new green, which was invented by Dr. VOGEL, in Berlin, and which we propose to call Sidorite green, from side- ros, tine Greek name for iron, is prepared by dissolving the precipitate obtained by mixing a solution of green copperas with one of yellow prussiate of potassa in ox- nile acid, adding to the same a soluti m of bichromate of potassa and a little sugar of lead The green pre- cipitate obtained is collected, washea out, and dried. According to the relative qualities of the three solu- tions, this coloran excellent paintmay be obtained from a deep bluish to the lightest green shade. The Firmness of Paper. IT is a well-known fact that linen fibres make .a finer paper than cotton ones; that unbienched material im- parts to it more firmness than that already affected by the bleaching process; that paper containing a hood deal of clay in its composition can not be as firmu and - as stron~ as that which is free from it, and other sim- ilar chemical substances. There have been, as yet, however, very few experiments made in oi-der to de- termine how great an influence these different ele- ments exert. But,gen emily speaking, the matter does not turn~simply upon the absolute firmness of the pa- per. The requirements of the manufacturer rest rather in a firmness th~t shall be both absolute and relativea compound ~rmness, so to speak. In some cases, however, it is only necessary to take into, consid- eration the absolute firmness of paper, as, for instancq that which is manufactured for use upon the rollers now coming into use in Morses system of telegraph- ing. A closer knowledge of this will, therefore, be. of great interest, particularly as regards the effect of differ- ent kinds of raw material and different metinods of man- ufacture. Experiments in this direction were lately made by Mr. ScHuLTz, a manufacturer in Eichberg, Germany. First of all, as regards the distinction be- tween paper that is manufactured by the old process of dipping and that which is made by machinery, it may be remarked thmat the felting of tine single fibres in thne case of dipped paper takes place in all directions with combplete uniformity. It is, therefore, natural that dipped paper possesses in all directions the same degree of firmness. This is not tine case, however; with paper prepared by means of a machine. We distinguish, in this case especially, two directions: the direction of the length, or that in which the paper stretches; and tIne transverse direction, or that in which it shrinks togetiner. But if already tinis distinction points us to- ward different degrees of firmness of the paper in these two directions, tine following observatioft will reader the fact still more apparent. If a piece, as, for instance, paper obtained by felting small fibres, is torn- at any point, in tIne first place, tine adhesion of tIne fibres ly- ng on either side of and parallel to each other and the rent must be overcome; secondly, the cohesion of the threads or fibres that are normal to the rupture muust likewise be overcome; indeed, every single thread muust be eitherbroken in twain or drawn Out front e remaining ones along its entire length. Of these two me Istin g qualities to be overcome, tine latter is most decidedly tine stronger. In accordance, therefore, with thnis, every kind of paper maying the greatest number of its fibres lying, as re~ards tineir length, in one and tine same diruition, must pO55~55 in that direction tine greatest absolute firmness. The machine paper above muentioned possesses time greatest absolute fimniness in the direction of tIne length of the fibres, and this direc- tion is, indeed, so apparent thmab in case of any piece of paper taken up at will, a practiced eye can tell at once the direction in which it passed through the ma- chine. But, in point of fact, experiments upon all time different kifids ~of paper tested by Mr. SCHULTZ, as regards their firmness, sinow the absolute firmness of a paper to be not overmuch greater in tho direction of its length than in its transverse direction. Experiiuents madewith fifteen different kinds of paper, encinofwhich 6

The Manufacturer and Builder. Painting the brick-work in positions is efficacious, bat has to be repeated, and; in the end, apt to make brick-work little, if any, cheaper than brown stone. in all these cases we are supposing the locality of the ~vork to be very exposed, as nrc a great many valuable residences. Of course, wooden structures are free from this annoyance; but the more substantial materials are now taking the lead of the t~e.-honored and once cherished frame, and so we must consider all the try- Ing necessities of location for brick, as being the most generally used of all materials for walls. Where the case is a trying one, slating the face of the wall ~vill be found a good practice, and ma~ be made very orna- mental by cutting off the lower ai~gles of each slate, in belts, ned by staining in different colors, as is done frequently -on Mansard roofs. The wall to be slated should first be furred in horizontal courses, and the weather or exposed face of the slate should be ei~ht inches, and not more. The furring pieces should be very well secured throughout, and be not less than three inches broad by one inch thick. The slates should be secured with copper nails, two at the shoul- ders and one at the tail. This cause of wall-damp is one that can not be too carefully guarded against, as it is one to which may be referred the early decay of many residences, as well as the inception of those pulmonary symptoms which so surely steal away the health, and ultimately the life, of many a victim. Persons building villas and bathing-lodges on the sea-shore should be cautious that sea-sand be not used in the mortar, as the presence of such material is cer- tain to create the damp by absorbing all the water in the atmosphere, this being the chemical effect of its saline property. With respect to the surface of walls of rooms, it may l)e as well to remark here that there are two ways of coating them besides wainscotingnamely, papering and painting. The former is objectionable, inasmuch as it is as porous as the plaster face it is intended to pro- tect; and when a room is uninhabited and unheated for a time, the natural damp of the atmosphere will be absorbed by the paper and lodge in the plaster, until the first lighting of a fire in the apartment draws it by degrees from its retreat. This process of exhala- tion must affect the durability of the wood-work, as well as the plastering of such rooms, not to speak of the torments of rheumatism to which poor humanity is rendered liable. As regards painting, its disadvan- tage in comparison with papering lies in its greater cost at first. In the question of duration as well as utility, it is the cheaper. The process of painting plaster-work is as fellows White-lead and linseed oil, with a little litharge to facilitate the drying, are mixed together to about the consistency of thin cream; a coating of this being ap- plied, the oil from it is sucked into the plaster in a few houis, leaving the white lead apparently dry upon the surface. Ia the course of a day or two, when this coat has sufficiently hardened, another is given a few de- grees thicker, the oil from which is partially absorbed, according to the nature of the plaster. This coat is made pretty thick, and if the absorption of the oil from the second coat has not been great, about one fou4h of spirits of turpentine is added; but where the absorption has been great, a iC55 propoition of spirits of turpentine is used. Into this coat the color- ing ingredients may be put which are to bring it near the shade of the finishing coat. Should the plaster now be thoroughly saturated, the flatting or finishing coat is applied. Before this is done, however, a fourth coat, thinned with equal proportioiis of oil and spirits of turpentine, is generally given, particularly where the work is wished to be of the most durable kind. The flatting or finishing coat is composed entirely of paintthat is, of white lead and the coloring ingre- dients, mixed together and ground in oil to an impalpable paste. This mixture is Qf .a very thick consistency, and must be thinned with spirits of tur- pentine until it will flow easily from the brush. The spirits of twpei~tine, being very volatile, evaporate entirely, leaving the surface of the paint of a very compact and hard nature. By this process the plaster is rendered incapable of absorption, and the, surface of it is hardened by the oil which it has sucked in from the first and second coats, and is thereby rendered less liable to breakage, with the great advantage of being washable. In another number of THE MANUFAcTURER AND BUILDER we will discuss the relative merits of some proposed coverings for Rails, with some suggestions of our own. The Utilization of Tin Scraps. I. UTILIZATION OF THE TIN. 1. Preparation of the Stannate of SodaFor the preparation of this product, which is largely used as a mordant in dyeing, the tin scraps are rolled up into spirals and placed in a wooden tank. For every one hundred pounds, ten pounds of sulphur and five pounds of caustic soda are added. The whole is then covered with water and steam turned on. By the chemical action which ensties, the scraps will very soon be freed from the tin, the blank iron making its appearance; The liquid is then drawn off, filtered, and evaporated, until a thin skin appears on the sur- face, when it is left to cool. Crystals of Glauber salt, which is a secondary product in this process, will ap- pear on the sides of the vessel; these are separated, and the remaining liquid is again filtered and evapo- rated to dryness. The hard cake obtained constitutes the stannate of soda, or Praeparirscdz., as it is called by the Germans. From one hundred pounds of scraps twelve to fifteen pounds of this salt are obtained, worth from 18 to 20 cents a pound. 2. Preparation of a new non-poisonous Green Paint. This new paint, which we propose to call Phanician Green, (because tin, one of its constituents, was first known among the Ph~nicians,) is cheap, does not fade, darkens with oil, and may be used as lime-and- water-color. It is made by mixing a solution of fifteen parts soda stannate with twelve parts blue copperas, the former being added to the latter. The precipitate obtained is brought up on a filter, well washed out, and dried. By mixitug it with a decoction of yellow- woo(l, or seine chrome-yellow, its color may be changed more into blue. - 3. Pin/c Uolor.-T his may also be applied as a paint, but it is of more value in the decoration of porcelain and Falence ware. It is similar to the red of the madder, and is prepared by mixing intimately three partsstannic acid with four parts chalk, two parts fine quartz sand, and one tenth part of bichromate of potassa, and ox-- posing the resulting mass in a 1-lessian crucible to white heat. The product obtained is finely powdered, washed out with water, and dried. The stannic acid is obtained by treating the tin scraps with aqua fortis, collecting the resulting white powder, and heating the same in the air. - 4. Yellow Bronze for WoodFirst, we prepare me tahhic tin by .inserting tin scraps in muriatic acid, which is placed in a glazed pot. When tIne tin is dis- solved, the liquid is transferred into another vessel, and new strips are inserted, this process being repeated till the liquid is saturated. After this, copper plates are hung in the same, on which, by galvanic action, tine tin will be precipitated as a spongy mass. The result- ing chloride of copper may be used iRstead of the bl~ie copperas in the preparation of the Phmnician green. The spongy mass is-washed out, dried, and mixed with equal parts of sulphur and sal ammoniac. The mixture is put in a glass retort and heated in a sand-bath, when the yellow bronze is obtained as a sublimate. - II. UTILIZATION OF THE IRON. ~. Prepceration of c Polishing Powder fom Glasses. The product to start with for the m~king of this excel- lent article is the green copperas, which is obtained by the oombination of oil of vitriol with iron. A solu- tion of the copperas, when treated with oxalic acid, will yield the powder, which only needs to be dried and exposed to heat. 6. Preparation of Iron GreenThis new green, which was invented by Dr. VOGEL, in Berlin, and which we propose to call Sidorite green, from side- ros, tine Greek name for iron, is prepared by dissolving the precipitate obtained by mixing a solution of green copperas with one of yellow prussiate of potassa in ox- nile acid, adding to the same a soluti m of bichromate of potassa and a little sugar of lead The green pre- cipitate obtained is collected, washea out, and dried. According to the relative qualities of the three solu- tions, this coloran excellent paintmay be obtained from a deep bluish to the lightest green shade. The Firmness of Paper. IT is a well-known fact that linen fibres make .a finer paper than cotton ones; that unbienched material im- parts to it more firmness than that already affected by the bleaching process; that paper containing a hood deal of clay in its composition can not be as firmu and - as stron~ as that which is free from it, and other sim- ilar chemical substances. There have been, as yet, however, very few experiments made in oi-der to de- termine how great an influence these different ele- ments exert. But,gen emily speaking, the matter does not turn~simply upon the absolute firmness of the pa- per. The requirements of the manufacturer rest rather in a firmness th~t shall be both absolute and relativea compound ~rmness, so to speak. In some cases, however, it is only necessary to take into, consid- eration the absolute firmness of paper, as, for instancq that which is manufactured for use upon the rollers now coming into use in Morses system of telegraph- ing. A closer knowledge of this will, therefore, be. of great interest, particularly as regards the effect of differ- ent kinds of raw material and different metinods of man- ufacture. Experiments in this direction were lately made by Mr. ScHuLTz, a manufacturer in Eichberg, Germany. First of all, as regards the distinction be- tween paper that is manufactured by the old process of dipping and that which is made by machinery, it may be remarked thmat the felting of tine single fibres in thne case of dipped paper takes place in all directions with combplete uniformity. It is, therefore, natural that dipped paper possesses in all directions the same degree of firmness. This is not tine case, however; with paper prepared by means of a machine. We distinguish, in this case especially, two directions: the direction of the length, or that in which the paper stretches; and tIne transverse direction, or that in which it shrinks togetiner. But if already tinis distinction points us to- ward different degrees of firmness of the paper in these two directions, tine following observatioft will reader the fact still more apparent. If a piece, as, for instance, paper obtained by felting small fibres, is torn- at any point, in tIne first place, tine adhesion of tIne fibres ly- ng on either side of and parallel to each other and the rent must be overcome; secondly, the cohesion of the threads or fibres that are normal to the rupture muust likewise be overcome; indeed, every single thread muust be eitherbroken in twain or drawn Out front e remaining ones along its entire length. Of these two me Istin g qualities to be overcome, tine latter is most decidedly tine stronger. In accordance, therefore, with thnis, every kind of paper maying the greatest number of its fibres lying, as re~ards tineir length, in one and tine same diruition, must pO55~55 in that direction tine greatest absolute firmness. The machine paper above muentioned possesses time greatest absolute fimniness in the direction of tIne length of the fibres, and this direc- tion is, indeed, so apparent thmab in case of any piece of paper taken up at will, a practiced eye can tell at once the direction in which it passed through the ma- chine. But, in point of fact, experiments upon all time different kifids ~of paper tested by Mr. SCHULTZ, as regards their firmness, sinow the absolute firmness of a paper to be not overmuch greater in tho direction of its length than in its transverse direction. Experiiuents madewith fifteen different kinds of paper, encinofwhich 6

The Manufacturer and Builder. Painting the brick-work in positions is efficacious, bat has to be repeated, and; in the end, apt to make brick-work little, if any, cheaper than brown stone. in all these cases we are supposing the locality of the ~vork to be very exposed, as nrc a great many valuable residences. Of course, wooden structures are free from this annoyance; but the more substantial materials are now taking the lead of the t~e.-honored and once cherished frame, and so we must consider all the try- Ing necessities of location for brick, as being the most generally used of all materials for walls. Where the case is a trying one, slating the face of the wall ~vill be found a good practice, and ma~ be made very orna- mental by cutting off the lower ai~gles of each slate, in belts, ned by staining in different colors, as is done frequently -on Mansard roofs. The wall to be slated should first be furred in horizontal courses, and the weather or exposed face of the slate should be ei~ht inches, and not more. The furring pieces should be very well secured throughout, and be not less than three inches broad by one inch thick. The slates should be secured with copper nails, two at the shoul- ders and one at the tail. This cause of wall-damp is one that can not be too carefully guarded against, as it is one to which may be referred the early decay of many residences, as well as the inception of those pulmonary symptoms which so surely steal away the health, and ultimately the life, of many a victim. Persons building villas and bathing-lodges on the sea-shore should be cautious that sea-sand be not used in the mortar, as the presence of such material is cer- tain to create the damp by absorbing all the water in the atmosphere, this being the chemical effect of its saline property. With respect to the surface of walls of rooms, it may l)e as well to remark here that there are two ways of coating them besides wainscotingnamely, papering and painting. The former is objectionable, inasmuch as it is as porous as the plaster face it is intended to pro- tect; and when a room is uninhabited and unheated for a time, the natural damp of the atmosphere will be absorbed by the paper and lodge in the plaster, until the first lighting of a fire in the apartment draws it by degrees from its retreat. This process of exhala- tion must affect the durability of the wood-work, as well as the plastering of such rooms, not to speak of the torments of rheumatism to which poor humanity is rendered liable. As regards painting, its disadvan- tage in comparison with papering lies in its greater cost at first. In the question of duration as well as utility, it is the cheaper. The process of painting plaster-work is as fellows White-lead and linseed oil, with a little litharge to facilitate the drying, are mixed together to about the consistency of thin cream; a coating of this being ap- plied, the oil from it is sucked into the plaster in a few houis, leaving the white lead apparently dry upon the surface. Ia the course of a day or two, when this coat has sufficiently hardened, another is given a few de- grees thicker, the oil from which is partially absorbed, according to the nature of the plaster. This coat is made pretty thick, and if the absorption of the oil from the second coat has not been great, about one fou4h of spirits of turpentine is added; but where the absorption has been great, a iC55 propoition of spirits of turpentine is used. Into this coat the color- ing ingredients may be put which are to bring it near the shade of the finishing coat. Should the plaster now be thoroughly saturated, the flatting or finishing coat is applied. Before this is done, however, a fourth coat, thinned with equal proportioiis of oil and spirits of turpentine, is generally given, particularly where the work is wished to be of the most durable kind. The flatting or finishing coat is composed entirely of paintthat is, of white lead and the coloring ingre- dients, mixed together and ground in oil to an impalpable paste. This mixture is Qf .a very thick consistency, and must be thinned with spirits of tur- pentine until it will flow easily from the brush. The spirits of twpei~tine, being very volatile, evaporate entirely, leaving the surface of the paint of a very compact and hard nature. By this process the plaster is rendered incapable of absorption, and the, surface of it is hardened by the oil which it has sucked in from the first and second coats, and is thereby rendered less liable to breakage, with the great advantage of being washable. In another number of THE MANUFAcTURER AND BUILDER we will discuss the relative merits of some proposed coverings for Rails, with some suggestions of our own. The Utilization of Tin Scraps. I. UTILIZATION OF THE TIN. 1. Preparation of the Stannate of SodaFor the preparation of this product, which is largely used as a mordant in dyeing, the tin scraps are rolled up into spirals and placed in a wooden tank. For every one hundred pounds, ten pounds of sulphur and five pounds of caustic soda are added. The whole is then covered with water and steam turned on. By the chemical action which ensties, the scraps will very soon be freed from the tin, the blank iron making its appearance; The liquid is then drawn off, filtered, and evaporated, until a thin skin appears on the sur- face, when it is left to cool. Crystals of Glauber salt, which is a secondary product in this process, will ap- pear on the sides of the vessel; these are separated, and the remaining liquid is again filtered and evapo- rated to dryness. The hard cake obtained constitutes the stannate of soda, or Praeparirscdz., as it is called by the Germans. From one hundred pounds of scraps twelve to fifteen pounds of this salt are obtained, worth from 18 to 20 cents a pound. 2. Preparation of a new non-poisonous Green Paint. This new paint, which we propose to call Phanician Green, (because tin, one of its constituents, was first known among the Ph~nicians,) is cheap, does not fade, darkens with oil, and may be used as lime-and- water-color. It is made by mixing a solution of fifteen parts soda stannate with twelve parts blue copperas, the former being added to the latter. The precipitate obtained is brought up on a filter, well washed out, and dried. By mixitug it with a decoction of yellow- woo(l, or seine chrome-yellow, its color may be changed more into blue. - 3. Pin/c Uolor.-T his may also be applied as a paint, but it is of more value in the decoration of porcelain and Falence ware. It is similar to the red of the madder, and is prepared by mixing intimately three partsstannic acid with four parts chalk, two parts fine quartz sand, and one tenth part of bichromate of potassa, and ox-- posing the resulting mass in a 1-lessian crucible to white heat. The product obtained is finely powdered, washed out with water, and dried. The stannic acid is obtained by treating the tin scraps with aqua fortis, collecting the resulting white powder, and heating the same in the air. - 4. Yellow Bronze for WoodFirst, we prepare me tahhic tin by .inserting tin scraps in muriatic acid, which is placed in a glazed pot. When tIne tin is dis- solved, the liquid is transferred into another vessel, and new strips are inserted, this process being repeated till the liquid is saturated. After this, copper plates are hung in the same, on which, by galvanic action, tine tin will be precipitated as a spongy mass. The result- ing chloride of copper may be used iRstead of the bl~ie copperas in the preparation of the Phmnician green. The spongy mass is-washed out, dried, and mixed with equal parts of sulphur and sal ammoniac. The mixture is put in a glass retort and heated in a sand-bath, when the yellow bronze is obtained as a sublimate. - II. UTILIZATION OF THE IRON. ~. Prepceration of c Polishing Powder fom Glasses. The product to start with for the m~king of this excel- lent article is the green copperas, which is obtained by the oombination of oil of vitriol with iron. A solu- tion of the copperas, when treated with oxalic acid, will yield the powder, which only needs to be dried and exposed to heat. 6. Preparation of Iron GreenThis new green, which was invented by Dr. VOGEL, in Berlin, and which we propose to call Sidorite green, from side- ros, tine Greek name for iron, is prepared by dissolving the precipitate obtained by mixing a solution of green copperas with one of yellow prussiate of potassa in ox- nile acid, adding to the same a soluti m of bichromate of potassa and a little sugar of lead The green pre- cipitate obtained is collected, washea out, and dried. According to the relative qualities of the three solu- tions, this coloran excellent paintmay be obtained from a deep bluish to the lightest green shade. The Firmness of Paper. IT is a well-known fact that linen fibres make .a finer paper than cotton ones; that unbienched material im- parts to it more firmness than that already affected by the bleaching process; that paper containing a hood deal of clay in its composition can not be as firmu and - as stron~ as that which is free from it, and other sim- ilar chemical substances. There have been, as yet, however, very few experiments made in oi-der to de- termine how great an influence these different ele- ments exert. But,gen emily speaking, the matter does not turn~simply upon the absolute firmness of the pa- per. The requirements of the manufacturer rest rather in a firmness th~t shall be both absolute and relativea compound ~rmness, so to speak. In some cases, however, it is only necessary to take into, consid- eration the absolute firmness of paper, as, for instancq that which is manufactured for use upon the rollers now coming into use in Morses system of telegraph- ing. A closer knowledge of this will, therefore, be. of great interest, particularly as regards the effect of differ- ent kinds of raw material and different metinods of man- ufacture. Experiments in this direction were lately made by Mr. ScHuLTz, a manufacturer in Eichberg, Germany. First of all, as regards the distinction be- tween paper that is manufactured by the old process of dipping and that which is made by machinery, it may be remarked thmat the felting of tine single fibres in thne case of dipped paper takes place in all directions with combplete uniformity. It is, therefore, natural that dipped paper possesses in all directions the same degree of firmness. This is not tine case, however; with paper prepared by means of a machine. We distinguish, in this case especially, two directions: the direction of the length, or that in which the paper stretches; and tIne transverse direction, or that in which it shrinks togetiner. But if already tinis distinction points us to- ward different degrees of firmness of the paper in these two directions, tine following observatioft will reader the fact still more apparent. If a piece, as, for instance, paper obtained by felting small fibres, is torn- at any point, in tIne first place, tine adhesion of tIne fibres ly- ng on either side of and parallel to each other and the rent must be overcome; secondly, the cohesion of the threads or fibres that are normal to the rupture muust likewise be overcome; indeed, every single thread muust be eitherbroken in twain or drawn Out front e remaining ones along its entire length. Of these two me Istin g qualities to be overcome, tine latter is most decidedly tine stronger. In accordance, therefore, with thnis, every kind of paper maying the greatest number of its fibres lying, as re~ards tineir length, in one and tine same diruition, must pO55~55 in that direction tine greatest absolute firmness. The machine paper above muentioned possesses time greatest absolute fimniness in the direction of tIne length of the fibres, and this direc- tion is, indeed, so apparent thmab in case of any piece of paper taken up at will, a practiced eye can tell at once the direction in which it passed through the ma- chine. But, in point of fact, experiments upon all time different kifids ~of paper tested by Mr. SCHULTZ, as regards their firmness, sinow the absolute firmness of a paper to be not overmuch greater in tho direction of its length than in its transverse direction. Experiiuents madewith fifteen different kinds of paper, encinofwhich 6 The Manufacturer and Builder. was made up of about th~e same number of linen and cotton fibres, and which had au average weight of five grammes per square foot, gave the following results: The average weight at which a strip one inch in width, taken in the direction of the length of its fibres, tore apart, was 18.2 lbs.; on the contrary, the ~weight at which an equally wide strip, taken in the transverse di- rection of its fibres, tore apart, was 12.04 lbs. It may be remarked that the above kinds of paper, upon being burnt, left behind an average of 0.8 per cent of ash. Experiments with gray wrapping paper, having a weight of nine and a half grammes per square foot, and leaving 13.7 per cent of ash, gave a rupture weight of 28.2 lbs. when the strips were taken in the direction of the length of the fibres, and 21.3 lbs. when taken in the transverse direction. Paper made for the most part of woolen fibres, with a weight of fifteen and a half grammes per square foot, and leaving 1.8 per cent of ash,. gave, respectively, 23.4 and 10.3 lbs. resistance to rupture. Paper manufactured of wood-fibres, six grammes per square foot in weight, with 0.2 per cent of ash after burning, gave, respectively, 23.4 and 10.3 lbs. resistance. The ratio of firmness in the direction of the length was, therefore, to that in the transverse direc- tion, as three to two. In reference to the effect of calen- dering upon the absolute firmness of paper, it may be remarked that it depends upon the resistance which the fibres of it offer to crushing; for, indeed, in case of calendering we must take this kind of firmness into account. As long as the pressure is not so great as to exceed the limits of elasticity of the single fibres, they will only be pressed nearer together. Their adhesion, and with it their absolute firmness, will be increased; the latter will not aiuount to very much, however, as it will be in exact proportion to the increase of the ad- hesion of the fibres. A fine printing paper, without any addition of wood-fibre in its manufacture, weigh- ing 3.8 grammes per square foot, and leaving 0.47 per cent of ash, gave the following results: Firmness in the Firmness in the direction of the transverse di- fibre length rection. Uncalendered 18.6 lbs 8.6 lbs. Calendered once 13.7 8.6 twice 18.7 9.1 A fine writing-paper likewise, without wood-fibre and without any addition of. clay, weighing. 5.3 grammes per square foot, gave by experiment the fob lowing numbers: Firmness along Across the the fibre, fibre. Uncalendered 20.5 lbs 14.8 lbs. Calendered. 22.0 iSA Wood-fibres, on the contrary, appear unable to offer great resistance to crushing. The limits of elasticity are exceeded even by a proportionally small amount of pressure, and the fibres themselves are so much in- jured that, in spite of their increased adhesion, the ab- solute firmness of the paper is less. The above men- tioned paper, iuade of wood-fibres only, with a firmness in the direction of its length of 23.4 lbs., and trans- versely of 16.3 lbs., gave, after calendering, in lieu of these figures, numbers of only about half tlieir value, namely, 12.8 and 8.4 lbs. In case of an uncalendered common paper, in the making of which thirty-three and one third per cent of wood-fibre was used, weighing five and nine tenths grammos per square foot, and burn- ing with a residue of 7.1 per, cent of ash, the firmness in the direction of the fibre length was found to be 24.7 lbs. ~ in the transverse direction, 10.3 lbs.; when calen- dered, ~he former was 20.0, the latter 14.1 lbs. How- ever great, therefore, may be the absolute firmness of the paper manufactured from wood-fibre, it appears that it is not a fitting-material forthe making of papers that are to receive much calendering or otherwise to be sub- jected to great pressure. Finally, as regards the influ- ence of clay in the composition of paper upoh its abso- lute firmness, two experiments were made with samples which differed from each other only in their percentage of this material. In the first case, a printing paper was used of 4.7 grammes weight per square foot, and with ~3 per cent ash residue. The resistanc~ to rupture, in the direction of the lepgth of the fibre, was 10.8 lbs.; in the cross direction, 12.5 lbs. On the contrary, a pa- per in all respects the same, with the exception of its containing a little more clay, so that in burning there was an ash residue of ten per cent, gave respectively the numbers 15.8 and 10.7 lbs. In the second experi- ment ordinary pap1er was used. It had a weight of five and three tenths grammes per square foot, and thirty- three and one third per cent of wood-fibre in the ma- terial of its manufacture. Uncalendered, a sample of this left an ash residue of 5.7 per cent; the resistance to rupture was in the two directions, respectively, 20.2 and 14.3 lbs. Tjie same kind of paper, calendered, left, after burning, 7.0 per cent residue of ash, and gave 12.1 lbs. resistance to rupture in the direction of the fibre length, and 11.9 lbs. resistance in the other, or transverse directionDeutsche Industrie-Zeitung. New City Buildings. 5PEOIFICATION5 AND GENERAL PROGRESS. THE decade is Renaissance mad, and promises to in- graft the ornate not only upon private residences, but upon more pretentious. public buildings and buildings for business purposes, of .which several re- markable examples are now in process of erection in various parts of the city. Of these the Park Bank building claims the preSminence, closely followed, however, by the new edifice ,on Broadway~ between Eighteenth and Nineteenth streets, which resembles it very minutely in frontal ornamentation. A third building, of some importance, considered as a copy of Stewarts up-town store, is being erected at the corner of Eleventh street and Broadway, which, however, may be described as a wooden structure veneered with ironbeams, rafters, supporters, and the like, with the exception of the columns, being of the former, mate- rial. The third edifice in the order mentionod occupies the whole square between Eighteenth and Nineteenth streets, has an elevation of six stories, and is intended to be one of the most complete palaces of business in the city. The material used is white marble, the style being very ornate Renaissance. The last-men- tioned building is less pretentious, has a Broadway front of fifty feet, with a depth of ,one hundred and twenty-five feet, and presents an elevation of six sto- ries. A fifth structure worthy of note is the new marble building at the corner of Broadway and Leonard street. In, point of appearance it presents a front of greater heaviness and solidity than either of the be- fore-mentioned, set off with rusticated marble-work. A sort of Roman air in contradistinction to the Grecian pervades the general manner of the fa~ade, and pleasingly distinguishes it~rom contiguous light- er structures. It has a Broadway frontage of about fifty feet, with a depth of double fifty on Leonard street. On Fourth avenue, the Young Mens Christian As- sociation have laid the corner-stone of a new edifice of rather-imposing proportions, which is hereafter to be used as the central officeof the Association. The style is Renaissance of the most erratic pattern, and embodies some distinctive features in its application quite worthy of more extended analysis than present space permits. The building has a Fourth avenue front of neariy one hundred feet, with an elevation o,f between eighty and ninety feet, divided without into only two stories. The entrance (main) is held by a tower divided into five stories; and it is the difference in story-division between the tower and the supple- mental structure which renders the whole, taken to- gether, rather peculiar in its effect. At the corner of Bleecker street and the Bowery another building of little pretension is creeping up- ward from story to story, making the second erected on this square during the past year; and with this must be concluded the list of larger structures now in process of erection. During the year, something more than a dozen of similar dimensions have been 7 completed, most important of which, as a fine example of the Moorish style of Spain and a very close copy of the Alhambra, is the new Jewish synagogue on Fifth avenue. Last, but somewhat more important than either, must be mentioned Booths new theatre5 of which a more elaborate description is reserved. The mania for the ornate may be said to have be- gun in 1865, which year was, in many respects, an era in the history of building in this city, especially, for business purposes. In fact, during that year .more structures of imposing proportions were begun and finished than in any previous or succeeding round of twelve months. These were mostly of exceedingly ornate style; and, as many of them were ware%~ouses, they mark ~he introduction of the ornate into busi- ness edifices. One point in the operations of the Department of Building merits mention. It is the universal tenden- cy to the naturalization of the Mansard roof, not only in buildings intended for ,business, but in those in- tended for private residence as well; and it is estima- ted that, during the twelve months past, not less.than one hundred old buildings have been unroof recapped with the Mansard. Of course, in many cases, the resuit has been to obtain the utmost incon- gruity of appearance; for the Mansard is no more am plicable to all styles of buildings than is the tradi- tional silk hat to all styles of face; and in remodel-, ing, what may be termed the physiognomy of a building must not be. forgotten. For structures of more than four stories, the Mansard roof is doubtless ornamental; but in those ,of lesser ~ei~ht,, its addi- tion resuits in an appearance which suggests a very little man with a very tall hat on. Then again, even in the case of lofty and imposing edifices, the roof of the day is not always in taste, and interferes sadly with the general unity of those which may happen to be of the Roman air rather than of the Grecian. The new building at the corner, of Broadway and Leonard street, for instance, would not properly take the Man- sard roof. In the way of private residences of what is termed the first class, the year has been very prolific, one hundred and twelve ,of these having been erected; of which twenty-six have been on, the up-town Astor property. They have been mostly of the traditionmiL twenty-five feet front, with four stories, and basement of the general pattern, the once stylish English base- ment having fallen into disfavor. The year exhibits, also, a gratifying decline in the number of tenement- houses, or buildings of tlio third class, which have been put up: In fact, the whdle number of such has fallen short of one hundred. In buildings ofthe second class ; that is, intended to accommodate a single family, but not strictly of the best constructionthe number ,has been very large, rangIng at something over one hundred and fifty; so thatit may be re~ marked that the past ,year has witnessed the erection of more buildings for the purposes ,of residence than any preceding since the department went into opera- tion. Fewer iron buildings, or specifications therefor, have been submitted than during the year 1867, while the mania for marble fronts has correspondingly increased; and the prospect is that, except for certain purposes, the rage for iron structures is over for the present. The number of specifications submitted during the month past has been over forty, of which the majori- ty were for first-class buildings for residence, a small minority being for business purposes. A TORPEDO of extraordinary power, it is reported, has been invented by an Englishman, Mr. WUfTE- READ, of Fiume, who has received $100,000 from the Austrian Government for his secret. The inventor offers to sell the exclusive right to use the torpedo to the British Government for $500,000, or will disclose the method of construction for $100,000, to be paid after a report on the merits of the invention, by a board of inc1uiry.

The Manufacturer and Builder. was made up of about th~e same number of linen and cotton fibres, and which had au average weight of five grammes per square foot, gave the following results: The average weight at which a strip one inch in width, taken in the direction of the length of its fibres, tore apart, was 18.2 lbs.; on the contrary, the ~weight at which an equally wide strip, taken in the transverse di- rection of its fibres, tore apart, was 12.04 lbs. It may be remarked that the above kinds of paper, upon being burnt, left behind an average of 0.8 per cent of ash. Experiments with gray wrapping paper, having a weight of nine and a half grammes per square foot, and leaving 13.7 per cent of ash, gave a rupture weight of 28.2 lbs. when the strips were taken in the direction of the length of the fibres, and 21.3 lbs. when taken in the transverse direction. Paper made for the most part of woolen fibres, with a weight of fifteen and a half grammes per square foot, and leaving 1.8 per cent of ash,. gave, respectively, 23.4 and 10.3 lbs. resistance to rupture. Paper manufactured of wood-fibres, six grammes per square foot in weight, with 0.2 per cent of ash after burning, gave, respectively, 23.4 and 10.3 lbs. resistance. The ratio of firmness in the direction of the length was, therefore, to that in the transverse direc- tion, as three to two. In reference to the effect of calen- dering upon the absolute firmness of paper, it may be remarked that it depends upon the resistance which the fibres of it offer to crushing; for, indeed, in case of calendering we must take this kind of firmness into account. As long as the pressure is not so great as to exceed the limits of elasticity of the single fibres, they will only be pressed nearer together. Their adhesion, and with it their absolute firmness, will be increased; the latter will not aiuount to very much, however, as it will be in exact proportion to the increase of the ad- hesion of the fibres. A fine printing paper, without any addition of wood-fibre in its manufacture, weigh- ing 3.8 grammes per square foot, and leaving 0.47 per cent of ash, gave the following results: Firmness in the Firmness in the direction of the transverse di- fibre length rection. Uncalendered 18.6 lbs 8.6 lbs. Calendered once 13.7 8.6 twice 18.7 9.1 A fine writing-paper likewise, without wood-fibre and without any addition of. clay, weighing. 5.3 grammes per square foot, gave by experiment the fob lowing numbers: Firmness along Across the the fibre, fibre. Uncalendered 20.5 lbs 14.8 lbs. Calendered. 22.0 iSA Wood-fibres, on the contrary, appear unable to offer great resistance to crushing. The limits of elasticity are exceeded even by a proportionally small amount of pressure, and the fibres themselves are so much in- jured that, in spite of their increased adhesion, the ab- solute firmness of the paper is less. The above men- tioned paper, iuade of wood-fibres only, with a firmness in the direction of its length of 23.4 lbs., and trans- versely of 16.3 lbs., gave, after calendering, in lieu of these figures, numbers of only about half tlieir value, namely, 12.8 and 8.4 lbs. In case of an uncalendered common paper, in the making of which thirty-three and one third per cent of wood-fibre was used, weighing five and nine tenths grammos per square foot, and burn- ing with a residue of 7.1 per, cent of ash, the firmness in the direction of the fibre length was found to be 24.7 lbs. ~ in the transverse direction, 10.3 lbs.; when calen- dered, ~he former was 20.0, the latter 14.1 lbs. How- ever great, therefore, may be the absolute firmness of the paper manufactured from wood-fibre, it appears that it is not a fitting-material forthe making of papers that are to receive much calendering or otherwise to be sub- jected to great pressure. Finally, as regards the influ- ence of clay in the composition of paper upoh its abso- lute firmness, two experiments were made with samples which differed from each other only in their percentage of this material. In the first case, a printing paper was used of 4.7 grammes weight per square foot, and with ~3 per cent ash residue. The resistanc~ to rupture, in the direction of the lepgth of the fibre, was 10.8 lbs.; in the cross direction, 12.5 lbs. On the contrary, a pa- per in all respects the same, with the exception of its containing a little more clay, so that in burning there was an ash residue of ten per cent, gave respectively the numbers 15.8 and 10.7 lbs. In the second experi- ment ordinary pap1er was used. It had a weight of five and three tenths grammes per square foot, and thirty- three and one third per cent of wood-fibre in the ma- terial of its manufacture. Uncalendered, a sample of this left an ash residue of 5.7 per cent; the resistance to rupture was in the two directions, respectively, 20.2 and 14.3 lbs. Tjie same kind of paper, calendered, left, after burning, 7.0 per cent residue of ash, and gave 12.1 lbs. resistance to rupture in the direction of the fibre length, and 11.9 lbs. resistance in the other, or transverse directionDeutsche Industrie-Zeitung. New City Buildings. 5PEOIFICATION5 AND GENERAL PROGRESS. THE decade is Renaissance mad, and promises to in- graft the ornate not only upon private residences, but upon more pretentious. public buildings and buildings for business purposes, of .which several re- markable examples are now in process of erection in various parts of the city. Of these the Park Bank building claims the preSminence, closely followed, however, by the new edifice ,on Broadway~ between Eighteenth and Nineteenth streets, which resembles it very minutely in frontal ornamentation. A third building, of some importance, considered as a copy of Stewarts up-town store, is being erected at the corner of Eleventh street and Broadway, which, however, may be described as a wooden structure veneered with ironbeams, rafters, supporters, and the like, with the exception of the columns, being of the former, mate- rial. The third edifice in the order mentionod occupies the whole square between Eighteenth and Nineteenth streets, has an elevation of six stories, and is intended to be one of the most complete palaces of business in the city. The material used is white marble, the style being very ornate Renaissance. The last-men- tioned building is less pretentious, has a Broadway front of fifty feet, with a depth of ,one hundred and twenty-five feet, and presents an elevation of six sto- ries. A fifth structure worthy of note is the new marble building at the corner of Broadway and Leonard street. In, point of appearance it presents a front of greater heaviness and solidity than either of the be- fore-mentioned, set off with rusticated marble-work. A sort of Roman air in contradistinction to the Grecian pervades the general manner of the fa~ade, and pleasingly distinguishes it~rom contiguous light- er structures. It has a Broadway frontage of about fifty feet, with a depth of double fifty on Leonard street. On Fourth avenue, the Young Mens Christian As- sociation have laid the corner-stone of a new edifice of rather-imposing proportions, which is hereafter to be used as the central officeof the Association. The style is Renaissance of the most erratic pattern, and embodies some distinctive features in its application quite worthy of more extended analysis than present space permits. The building has a Fourth avenue front of neariy one hundred feet, with an elevation o,f between eighty and ninety feet, divided without into only two stories. The entrance (main) is held by a tower divided into five stories; and it is the difference in story-division between the tower and the supple- mental structure which renders the whole, taken to- gether, rather peculiar in its effect. At the corner of Bleecker street and the Bowery another building of little pretension is creeping up- ward from story to story, making the second erected on this square during the past year; and with this must be concluded the list of larger structures now in process of erection. During the year, something more than a dozen of similar dimensions have been 7 completed, most important of which, as a fine example of the Moorish style of Spain and a very close copy of the Alhambra, is the new Jewish synagogue on Fifth avenue. Last, but somewhat more important than either, must be mentioned Booths new theatre5 of which a more elaborate description is reserved. The mania for the ornate may be said to have be- gun in 1865, which year was, in many respects, an era in the history of building in this city, especially, for business purposes. In fact, during that year .more structures of imposing proportions were begun and finished than in any previous or succeeding round of twelve months. These were mostly of exceedingly ornate style; and, as many of them were ware%~ouses, they mark ~he introduction of the ornate into busi- ness edifices. One point in the operations of the Department of Building merits mention. It is the universal tenden- cy to the naturalization of the Mansard roof, not only in buildings intended for ,business, but in those in- tended for private residence as well; and it is estima- ted that, during the twelve months past, not less.than one hundred old buildings have been unroof recapped with the Mansard. Of course, in many cases, the resuit has been to obtain the utmost incon- gruity of appearance; for the Mansard is no more am plicable to all styles of buildings than is the tradi- tional silk hat to all styles of face; and in remodel-, ing, what may be termed the physiognomy of a building must not be. forgotten. For structures of more than four stories, the Mansard roof is doubtless ornamental; but in those ,of lesser ~ei~ht,, its addi- tion resuits in an appearance which suggests a very little man with a very tall hat on. Then again, even in the case of lofty and imposing edifices, the roof of the day is not always in taste, and interferes sadly with the general unity of those which may happen to be of the Roman air rather than of the Grecian. The new building at the corner, of Broadway and Leonard street, for instance, would not properly take the Man- sard roof. In the way of private residences of what is termed the first class, the year has been very prolific, one hundred and twelve ,of these having been erected; of which twenty-six have been on, the up-town Astor property. They have been mostly of the traditionmiL twenty-five feet front, with four stories, and basement of the general pattern, the once stylish English base- ment having fallen into disfavor. The year exhibits, also, a gratifying decline in the number of tenement- houses, or buildings of tlio third class, which have been put up: In fact, the whdle number of such has fallen short of one hundred. In buildings ofthe second class ; that is, intended to accommodate a single family, but not strictly of the best constructionthe number ,has been very large, rangIng at something over one hundred and fifty; so thatit may be re~ marked that the past ,year has witnessed the erection of more buildings for the purposes ,of residence than any preceding since the department went into opera- tion. Fewer iron buildings, or specifications therefor, have been submitted than during the year 1867, while the mania for marble fronts has correspondingly increased; and the prospect is that, except for certain purposes, the rage for iron structures is over for the present. The number of specifications submitted during the month past has been over forty, of which the majori- ty were for first-class buildings for residence, a small minority being for business purposes. A TORPEDO of extraordinary power, it is reported, has been invented by an Englishman, Mr. WUfTE- READ, of Fiume, who has received $100,000 from the Austrian Government for his secret. The inventor offers to sell the exclusive right to use the torpedo to the British Government for $500,000, or will disclose the method of construction for $100,000, to be paid after a report on the merits of the invention, by a board of inc1uiry. The Manufacturer and Builder. Have you ever looked through a Microscope? WERE this question proposed to the readers of THE MANUFACTURER AND BUILDER, how many would an- swer in the affirmative? We venture to say that barely one in a hundred of our readers, intelligent though they be, could say Yes! We can only say we sincerely pity the unfortunate majority that never have; for they know not what pleasure and informa- tion they have deprived themselves of. No application of science yields so rich a return for the time and mo- ney expended in its purchase and use, as a good com- pound microscope. All around usin the animiVl, the veget~Me, and the mineral kingdomare myriads of obj ects, of marvelous beauty) shut out from our ordi- nary vision, and of which, but for the microscope, we would be utterly ignorant. By their revelation we more fully realize the omnipotence of Him who has created not only the obj ects of greater magnitude to which we are accustomed, but has also invested with life, and fashioned with beauty of design and intricacy of workmanship, the mere atom invisible to the unaid- ed eye. The microscope unfolds and opens to our view this hitherto unexplored world. As an insfru- meat of research, it is peculiar in the number, one might almost say universality, of pursuits in which it is of use. When viewing the beautiful geometric forms of crystalline texture with which the mineralogist has to do, he feels its need for the accurate measurement of their angles and the determination of their various axes. To the geologist, delving far down into the earths interior, its aid is essential for the examination of the various strata and the fossils therein contained. The physician, guided by its unerring light, plunges deep into anatomical research, and even demands its assistance in the making up of his diagnosis of disease. The druggist, keenly sensitive to any adulteration of his drugs, rej ects at once every atticle which the mi- croscope tells him is otherwise than pure. The mer chant, desirous of avoiding fraudulent traffic, deter- mines by its agency whether the fibres of his material are of wool, or cotton, or silk. The grocer saves him- self from loss, both in money and reputation, when the microscope reveals to him the admixture of foreign and oftentimes harmful ingredients in the various arti- cles of food which he exposes for sale. The artisan, the manufacturer, the builder, will find it of service in the determination of the composition, the durability, and the adaptation for specific uses of the materials employed in their several avocations. In a word, it is ready, in almost every pursuit, to lend a helping hand, and when not called upon for purposes of utility, is ever and anon ready to assist one in whiling away a leisure hour in the way of pleasure and amusement. Microscopic investigations have not as yet been pur- sued in this country with the same wide-spread zeal as in the Old World, though, nevertheless, we have among us many devoted microscopists whose attain- ments are equal to those of European observers. In the minds of most persons there exists an idea that the instrument is of an extremely scientific character, requiring close study; that it is apt to injure the eye- sight, and that it is very costly. All that is far from true. Any one of ordinary intelligence can, in half an hour, teach himself nil that is needful for the success- ful manipulation of the microscope, and will be sur- prised to find how many objects of beauty and interest he discovers ready to his hand in the air, earth, and waters. As regards any injury to the eyesight, we can only say that we have had the acquaintance of many hard-working microscopists, and have yet to hear of a single instance of damage thereto. The most devoted microscopist of this century, the celebrated EilEEN- BERG, of Germany, has within this year completed his fiftieth year of professional labors, having for all this period given a portion of each day to microscopic in- vestigations, and for many years with very imperfect instruments. Yet his eye is not dim, nor his natural force abated. However true it may formerly have been that a good croscope was of necessity costly, time has wrought a great change in this as well as in many other things. A better instrument can now be purchased for any given sum than the last generation could have pro- cured for three times the amount. It is also a gratifying fact to record, that American skill has made rapid strides in optical science, particularly as regards the construction of microscopes and microscopic lenses, the superiority of American workmanship having been acknowledged at the late Paris Exposition. In this article we desire to introduce to our readers two well-made American microscopes adapted to general use The Popular Microscope, of which we give an illus- tration one third the natural size, is designed for that large number of persons who desire a good but cheap instrument, either for the study of natural science or in the detection of adulterations in food, medicine, ar- ticles of trade, etc. It is recommended for its shhpli- city of construction, ease of manipulation, and low price. It stands nine inches high has rack-work for and will, with the highest pow ~cadi!y resolve fine lines and spaces, 10,000 to the ii~ch, which occur-on many beautiful microscopic be! is, such, for instance, as are found in guano, Tripoli polishing powder, in the earth upon which Richmond, Virginia, is built, and in soundings from the bed of the ocean. The Students Microscope is an instrument of finer finish than the Popular, one with more delicate focal adjustments. It stands twelve inches high, and is furnished with achromatic lenses affording a range of magnifying power from 50 io 400 diameters, or from 2500 to 160,000 areas. With these high powers the globuies of the blood are fully brought out, 4nd the characteristics in rhing the blood of different ani- mals are distinctly visible. A microscopic photograph of the Lords Prayer, contained in the 1-10,000th part of a square inch, the letters being 4000 to the inch, we have distinctly read by the aid of this student s mi- croscope. It will also resolve lines and spaces as fine as 30,000 to the inch. It may be interestin~ to many of our readers to he informed that even this measure- ment, 50 minute, is by no means the finest work in this line that nature has produced. We have now before us a delicate microscopic shell, invisible to the naked eye, found in the waters of the Central Park, New-York, upon which there are 80,000 to the inch. NOBERT, of Prussia, a skilled mechanician, has even sought to compete with nature, and has, by some pro- cess known only to himself, caused the diamond to cut a series of parallel lines on plates of glass, even finer than 80,000 to the inch, constituting a most deli- cate and valuable test for defining the power of the most perfect microscopic lenses. The Mechanic and his Work. IN all times and in all communities persons skilled in any kind of workmauship have been highly es- teemed. We find honorable mention made of TUBAL CAIN, who was an instructor of artificers in brass and iron. AARON, although the brother of the first of the prophets, seems, in the construction of the golden calf and the serpent, to have been possessed of a remarkable degree of manual skill, while the highly educated, elo- quent, and logical St. PAUL was trained to the business of a tent-maker. The Greeks placed a worker among their celestial gods, and VULcAN, however much black- erred and garment-soiled in his labors, was considered on that account none the less a god. Examples nearer our own time are presented in the case of FRANKLIN, FULTON, WATT, RITTENHOUSE, STEPHENSON, Enics- SON, and many others who have proved that in the employment of the hands there is no natural degrada- tion; and that, whatever may be the prejudices of some, manual callings may be followed consistently with the possession and use of every high, ennobling gift; and farther, that the duties of a mechanic should not ex- empt him from contributing his share to the worth and literary reputation of his country. In no country does the mechanic hold a better position than in this, and what is more, there is no country which grants him higher and more useful privilegeh When we glance at our manufactories, we see, for the most part, capital judiciously invested, and labor rightly directed. We see improvement in mans condition as a social being, progress in intelligence, advancement in skill, and a higher usthetic culture. In a word, industry meets with its just reward, and well-directed enterprise with corresponding success. We see the mechanic free to speak, act, invent, and construct, to move forward in his industrial career, spurred on by incentives that can only be found in the body of a free people. The respect for labor shown in this country, the encouragement given to all branches of education, the facilities exist- ing in many free institutions, the excellent opportuni- ties for mental improvement open to all, prove that there is no degree of distinction in, and even beyond his ordinary sphere, which the mechanic can not reach, if he make a proper use of the opportunities presented to him. The mechanic, as a mere workman, a mere adjusting the focus, and is furnished with achromatic lenses, affording various magnifying powers, ranging from 50 to 200 diameters, or Prom 2500 to 40.000 ardas, laborer, as a simple worker of metals or compounder 8 The Popular Xicroscope. is- The ~fu~enf~s Microscope.

The Manufacturer and Builder. Have you ever looked through a Microscope? WERE this question proposed to the readers of THE MANUFACTURER AND BUILDER, how many would an- swer in the affirmative? We venture to say that barely one in a hundred of our readers, intelligent though they be, could say Yes! We can only say we sincerely pity the unfortunate majority that never have; for they know not what pleasure and informa- tion they have deprived themselves of. No application of science yields so rich a return for the time and mo- ney expended in its purchase and use, as a good com- pound microscope. All around usin the animiVl, the veget~Me, and the mineral kingdomare myriads of obj ects, of marvelous beauty) shut out from our ordi- nary vision, and of which, but for the microscope, we would be utterly ignorant. By their revelation we more fully realize the omnipotence of Him who has created not only the obj ects of greater magnitude to which we are accustomed, but has also invested with life, and fashioned with beauty of design and intricacy of workmanship, the mere atom invisible to the unaid- ed eye. The microscope unfolds and opens to our view this hitherto unexplored world. As an insfru- meat of research, it is peculiar in the number, one might almost say universality, of pursuits in which it is of use. When viewing the beautiful geometric forms of crystalline texture with which the mineralogist has to do, he feels its need for the accurate measurement of their angles and the determination of their various axes. To the geologist, delving far down into the earths interior, its aid is essential for the examination of the various strata and the fossils therein contained. The physician, guided by its unerring light, plunges deep into anatomical research, and even demands its assistance in the making up of his diagnosis of disease. The druggist, keenly sensitive to any adulteration of his drugs, rej ects at once every atticle which the mi- croscope tells him is otherwise than pure. The mer chant, desirous of avoiding fraudulent traffic, deter- mines by its agency whether the fibres of his material are of wool, or cotton, or silk. The grocer saves him- self from loss, both in money and reputation, when the microscope reveals to him the admixture of foreign and oftentimes harmful ingredients in the various arti- cles of food which he exposes for sale. The artisan, the manufacturer, the builder, will find it of service in the determination of the composition, the durability, and the adaptation for specific uses of the materials employed in their several avocations. In a word, it is ready, in almost every pursuit, to lend a helping hand, and when not called upon for purposes of utility, is ever and anon ready to assist one in whiling away a leisure hour in the way of pleasure and amusement. Microscopic investigations have not as yet been pur- sued in this country with the same wide-spread zeal as in the Old World, though, nevertheless, we have among us many devoted microscopists whose attain- ments are equal to those of European observers. In the minds of most persons there exists an idea that the instrument is of an extremely scientific character, requiring close study; that it is apt to injure the eye- sight, and that it is very costly. All that is far from true. Any one of ordinary intelligence can, in half an hour, teach himself nil that is needful for the success- ful manipulation of the microscope, and will be sur- prised to find how many objects of beauty and interest he discovers ready to his hand in the air, earth, and waters. As regards any injury to the eyesight, we can only say that we have had the acquaintance of many hard-working microscopists, and have yet to hear of a single instance of damage thereto. The most devoted microscopist of this century, the celebrated EilEEN- BERG, of Germany, has within this year completed his fiftieth year of professional labors, having for all this period given a portion of each day to microscopic in- vestigations, and for many years with very imperfect instruments. Yet his eye is not dim, nor his natural force abated. However true it may formerly have been that a good croscope was of necessity costly, time has wrought a great change in this as well as in many other things. A better instrument can now be purchased for any given sum than the last generation could have pro- cured for three times the amount. It is also a gratifying fact to record, that American skill has made rapid strides in optical science, particularly as regards the construction of microscopes and microscopic lenses, the superiority of American workmanship having been acknowledged at the late Paris Exposition. In this article we desire to introduce to our readers two well-made American microscopes adapted to general use The Popular Microscope, of which we give an illus- tration one third the natural size, is designed for that large number of persons who desire a good but cheap instrument, either for the study of natural science or in the detection of adulterations in food, medicine, ar- ticles of trade, etc. It is recommended for its shhpli- city of construction, ease of manipulation, and low price. It stands nine inches high has rack-work for and will, with the highest pow ~cadi!y resolve fine lines and spaces, 10,000 to the ii~ch, which occur-on many beautiful microscopic be! is, such, for instance, as are found in guano, Tripoli polishing powder, in the earth upon which Richmond, Virginia, is built, and in soundings from the bed of the ocean. The Students Microscope is an instrument of finer finish than the Popular, one with more delicate focal adjustments. It stands twelve inches high, and is furnished with achromatic lenses affording a range of magnifying power from 50 io 400 diameters, or from 2500 to 160,000 areas. With these high powers the globuies of the blood are fully brought out, 4nd the characteristics in rhing the blood of different ani- mals are distinctly visible. A microscopic photograph of the Lords Prayer, contained in the 1-10,000th part of a square inch, the letters being 4000 to the inch, we have distinctly read by the aid of this student s mi- croscope. It will also resolve lines and spaces as fine as 30,000 to the inch. It may be interestin~ to many of our readers to he informed that even this measure- ment, 50 minute, is by no means the finest work in this line that nature has produced. We have now before us a delicate microscopic shell, invisible to the naked eye, found in the waters of the Central Park, New-York, upon which there are 80,000 to the inch. NOBERT, of Prussia, a skilled mechanician, has even sought to compete with nature, and has, by some pro- cess known only to himself, caused the diamond to cut a series of parallel lines on plates of glass, even finer than 80,000 to the inch, constituting a most deli- cate and valuable test for defining the power of the most perfect microscopic lenses. The Mechanic and his Work. IN all times and in all communities persons skilled in any kind of workmauship have been highly es- teemed. We find honorable mention made of TUBAL CAIN, who was an instructor of artificers in brass and iron. AARON, although the brother of the first of the prophets, seems, in the construction of the golden calf and the serpent, to have been possessed of a remarkable degree of manual skill, while the highly educated, elo- quent, and logical St. PAUL was trained to the business of a tent-maker. The Greeks placed a worker among their celestial gods, and VULcAN, however much black- erred and garment-soiled in his labors, was considered on that account none the less a god. Examples nearer our own time are presented in the case of FRANKLIN, FULTON, WATT, RITTENHOUSE, STEPHENSON, Enics- SON, and many others who have proved that in the employment of the hands there is no natural degrada- tion; and that, whatever may be the prejudices of some, manual callings may be followed consistently with the possession and use of every high, ennobling gift; and farther, that the duties of a mechanic should not ex- empt him from contributing his share to the worth and literary reputation of his country. In no country does the mechanic hold a better position than in this, and what is more, there is no country which grants him higher and more useful privilegeh When we glance at our manufactories, we see, for the most part, capital judiciously invested, and labor rightly directed. We see improvement in mans condition as a social being, progress in intelligence, advancement in skill, and a higher usthetic culture. In a word, industry meets with its just reward, and well-directed enterprise with corresponding success. We see the mechanic free to speak, act, invent, and construct, to move forward in his industrial career, spurred on by incentives that can only be found in the body of a free people. The respect for labor shown in this country, the encouragement given to all branches of education, the facilities exist- ing in many free institutions, the excellent opportuni- ties for mental improvement open to all, prove that there is no degree of distinction in, and even beyond his ordinary sphere, which the mechanic can not reach, if he make a proper use of the opportunities presented to him. The mechanic, as a mere workman, a mere adjusting the focus, and is furnished with achromatic lenses, affording various magnifying powers, ranging from 50 to 200 diameters, or Prom 2500 to 40.000 ardas, laborer, as a simple worker of metals or compounder 8 The Popular Xicroscope. is- The ~fu~enf~s Microscope.

The Manufacturer and Builder. Have you ever looked through a Microscope? WERE this question proposed to the readers of THE MANUFACTURER AND BUILDER, how many would an- swer in the affirmative? We venture to say that barely one in a hundred of our readers, intelligent though they be, could say Yes! We can only say we sincerely pity the unfortunate majority that never have; for they know not what pleasure and informa- tion they have deprived themselves of. No application of science yields so rich a return for the time and mo- ney expended in its purchase and use, as a good com- pound microscope. All around usin the animiVl, the veget~Me, and the mineral kingdomare myriads of obj ects, of marvelous beauty) shut out from our ordi- nary vision, and of which, but for the microscope, we would be utterly ignorant. By their revelation we more fully realize the omnipotence of Him who has created not only the obj ects of greater magnitude to which we are accustomed, but has also invested with life, and fashioned with beauty of design and intricacy of workmanship, the mere atom invisible to the unaid- ed eye. The microscope unfolds and opens to our view this hitherto unexplored world. As an insfru- meat of research, it is peculiar in the number, one might almost say universality, of pursuits in which it is of use. When viewing the beautiful geometric forms of crystalline texture with which the mineralogist has to do, he feels its need for the accurate measurement of their angles and the determination of their various axes. To the geologist, delving far down into the earths interior, its aid is essential for the examination of the various strata and the fossils therein contained. The physician, guided by its unerring light, plunges deep into anatomical research, and even demands its assistance in the making up of his diagnosis of disease. The druggist, keenly sensitive to any adulteration of his drugs, rej ects at once every atticle which the mi- croscope tells him is otherwise than pure. The mer chant, desirous of avoiding fraudulent traffic, deter- mines by its agency whether the fibres of his material are of wool, or cotton, or silk. The grocer saves him- self from loss, both in money and reputation, when the microscope reveals to him the admixture of foreign and oftentimes harmful ingredients in the various arti- cles of food which he exposes for sale. The artisan, the manufacturer, the builder, will find it of service in the determination of the composition, the durability, and the adaptation for specific uses of the materials employed in their several avocations. In a word, it is ready, in almost every pursuit, to lend a helping hand, and when not called upon for purposes of utility, is ever and anon ready to assist one in whiling away a leisure hour in the way of pleasure and amusement. Microscopic investigations have not as yet been pur- sued in this country with the same wide-spread zeal as in the Old World, though, nevertheless, we have among us many devoted microscopists whose attain- ments are equal to those of European observers. In the minds of most persons there exists an idea that the instrument is of an extremely scientific character, requiring close study; that it is apt to injure the eye- sight, and that it is very costly. All that is far from true. Any one of ordinary intelligence can, in half an hour, teach himself nil that is needful for the success- ful manipulation of the microscope, and will be sur- prised to find how many objects of beauty and interest he discovers ready to his hand in the air, earth, and waters. As regards any injury to the eyesight, we can only say that we have had the acquaintance of many hard-working microscopists, and have yet to hear of a single instance of damage thereto. The most devoted microscopist of this century, the celebrated EilEEN- BERG, of Germany, has within this year completed his fiftieth year of professional labors, having for all this period given a portion of each day to microscopic in- vestigations, and for many years with very imperfect instruments. Yet his eye is not dim, nor his natural force abated. However true it may formerly have been that a good croscope was of necessity costly, time has wrought a great change in this as well as in many other things. A better instrument can now be purchased for any given sum than the last generation could have pro- cured for three times the amount. It is also a gratifying fact to record, that American skill has made rapid strides in optical science, particularly as regards the construction of microscopes and microscopic lenses, the superiority of American workmanship having been acknowledged at the late Paris Exposition. In this article we desire to introduce to our readers two well-made American microscopes adapted to general use The Popular Microscope, of which we give an illus- tration one third the natural size, is designed for that large number of persons who desire a good but cheap instrument, either for the study of natural science or in the detection of adulterations in food, medicine, ar- ticles of trade, etc. It is recommended for its shhpli- city of construction, ease of manipulation, and low price. It stands nine inches high has rack-work for and will, with the highest pow ~cadi!y resolve fine lines and spaces, 10,000 to the ii~ch, which occur-on many beautiful microscopic be! is, such, for instance, as are found in guano, Tripoli polishing powder, in the earth upon which Richmond, Virginia, is built, and in soundings from the bed of the ocean. The Students Microscope is an instrument of finer finish than the Popular, one with more delicate focal adjustments. It stands twelve inches high, and is furnished with achromatic lenses affording a range of magnifying power from 50 io 400 diameters, or from 2500 to 160,000 areas. With these high powers the globuies of the blood are fully brought out, 4nd the characteristics in rhing the blood of different ani- mals are distinctly visible. A microscopic photograph of the Lords Prayer, contained in the 1-10,000th part of a square inch, the letters being 4000 to the inch, we have distinctly read by the aid of this student s mi- croscope. It will also resolve lines and spaces as fine as 30,000 to the inch. It may be interestin~ to many of our readers to he informed that even this measure- ment, 50 minute, is by no means the finest work in this line that nature has produced. We have now before us a delicate microscopic shell, invisible to the naked eye, found in the waters of the Central Park, New-York, upon which there are 80,000 to the inch. NOBERT, of Prussia, a skilled mechanician, has even sought to compete with nature, and has, by some pro- cess known only to himself, caused the diamond to cut a series of parallel lines on plates of glass, even finer than 80,000 to the inch, constituting a most deli- cate and valuable test for defining the power of the most perfect microscopic lenses. The Mechanic and his Work. IN all times and in all communities persons skilled in any kind of workmauship have been highly es- teemed. We find honorable mention made of TUBAL CAIN, who was an instructor of artificers in brass and iron. AARON, although the brother of the first of the prophets, seems, in the construction of the golden calf and the serpent, to have been possessed of a remarkable degree of manual skill, while the highly educated, elo- quent, and logical St. PAUL was trained to the business of a tent-maker. The Greeks placed a worker among their celestial gods, and VULcAN, however much black- erred and garment-soiled in his labors, was considered on that account none the less a god. Examples nearer our own time are presented in the case of FRANKLIN, FULTON, WATT, RITTENHOUSE, STEPHENSON, Enics- SON, and many others who have proved that in the employment of the hands there is no natural degrada- tion; and that, whatever may be the prejudices of some, manual callings may be followed consistently with the possession and use of every high, ennobling gift; and farther, that the duties of a mechanic should not ex- empt him from contributing his share to the worth and literary reputation of his country. In no country does the mechanic hold a better position than in this, and what is more, there is no country which grants him higher and more useful privilegeh When we glance at our manufactories, we see, for the most part, capital judiciously invested, and labor rightly directed. We see improvement in mans condition as a social being, progress in intelligence, advancement in skill, and a higher usthetic culture. In a word, industry meets with its just reward, and well-directed enterprise with corresponding success. We see the mechanic free to speak, act, invent, and construct, to move forward in his industrial career, spurred on by incentives that can only be found in the body of a free people. The respect for labor shown in this country, the encouragement given to all branches of education, the facilities exist- ing in many free institutions, the excellent opportuni- ties for mental improvement open to all, prove that there is no degree of distinction in, and even beyond his ordinary sphere, which the mechanic can not reach, if he make a proper use of the opportunities presented to him. The mechanic, as a mere workman, a mere adjusting the focus, and is furnished with achromatic lenses, affording various magnifying powers, ranging from 50 to 200 diameters, or Prom 2500 to 40.000 ardas, laborer, as a simple worker of metals or compounder 8 The Popular Xicroscope. is- The ~fu~enf~s Microscope. The Manufacturer and Builder. of ingredients, is, comparatively speaking, only half useful. He labors as it were oniy to live. As long as he does this, without mental exercise) there will be lit- tle or no advancement made in his industrial pursuits. If the workman, on the other hand, by thought and attention, aims at higher degrees of excellence, his work will very soon bear witness to his more than or- dinary effort. With all the latent powers of the mind quickened and set to work in the study of the arts and sciences, a world, as it were, of wonders will often be brought to view. The man who has in charge the lives of hundreds and the preservation of valuable property as he stands by his steam-boiler and engine on land or at sea, should know something more than to open a valve, use an oil- can, or handle a shovel. The pressure and nature of steam, the strength of materials, the nature of latent heat, economy of fuel, construction, composition of forces, management, and remedies in case of accidents, are subjects which should receive his closest attentioa and study. It is a fact that, at the present day, there are hundreds of men who go through the old system of manufacturing articles of daily consumptionof food especiallywho are totally ignorant of the nature of the ingredients they handle, or the laws which govern, or the chemical cl~nges which take place at the vari- ous stages of the processes employed. For the full development of the mechanic, or any one intended for pursuits connected with the art of construction, they should have a theoretical as well as a practical educa- tion ; they should be taught fundamental rules con- nected with their profession. Every mechanic and artisan, every manufacturer and operative, has, in his respective calling, a field of knowledge which requires constant tilling to bring its hidden treasures to light. It is absurd, says Mr. FAIRBAmN, to talk against theory, as if a knowledge of the exact sciences was a dangerous and a useless attainment; nothing can be more erroneous than this impression, as on close in- spection there is no practice without theory any more than there is no effect without a cause. In the mechan- ical arts, how difficult, precarious, and unsatisfactory are the reasonings of men unacquainted with first principles, and how very often does that deficiency lead them into mal-construction and those errors which a knowledge of science would teach them to avoid. Theory as well as practice, the fundamental princi- ples of cause and effect in all operations, demand alike attention and study from all those engaged in such pursuits. Reversible Seats. IN the general progress that charactdrizes the pre- sent age, and that particularly in the department of practical mechanics, the commonplace but withal very necessary matter of ~eats has not been forgotten. Comfort, convenience, and adaptation as regards physiological considerations of health are the chief ends to be secured in the construction of a seat. The march of invention has pretty nearly swept away the rude, rickety old bench of the country, or village. school-house, with its four legs of unequal lengths, andwoe to the uneasy urchin of eightits surplus- t~e of slivers. Seats, neatly made, with reversible backs which enable the occupant to face either way, are now quite frequently met with, even in the school- houses of the rural districts. They have their place in the lecture-room, the church, and, above all, in our rail- road-cars. But it may be remarked that the reversible seat hitherto in use, however convenient, was without a back. It should be so constructed that an adjust- ment of the seat can be made at the same time with the back. It is very clear that, in order to conduce to comfort, and at the same time to conform to the re- quirements of health, the seat proper shouid be mov- able, so that, when the back is set at any angle, it may be inclined at will downward and backward from the front edge. By such an arrangement, and such only, will the necessary requirements all be fulfilled. The seats represented by the accompanying illustrations combine all these aids to comfort, convenienee, and health. They were patented by W. H. JOEcKEL in the years 1861 and 1868, and are now manufactured by ROBERT PATON, 26 Grove street; New-York City. Fig. 1 is a seat calculated for school-houses, lecture- rooms, and railroad-cars. The sear ~ pivoted on a rod or axis under the seat, connected by a forked rod to an eccentric on the arm of the seat at either end, to which is pivoted, also, the arms supporting the back. As that is lifted and thrown over, the motion of the back compels, by means of the eccentric, a similar motion, although in a less degree, to the seat itself~ tilting it slightly back, and holding it and the back in position by the weight of the person occupy- ing the seat, both back and seat being governed, in their relative positions by the occupant of the seat. Fig. 2 is another form of the seat, presenting cushioned side-pieces for the arms to rest upon in whatever position the back may be. Its connections and action are similar to that intended for the lecture- room, the seat being tilted or inclined with the move- ment of the back. The back is hung on a pivot like a pendulum, and any number of seats may be connected in a line by means of a rod, and the backs reversed simultaneously, one lock fastening them all. They are simple as regards method of construction and operation, nor are they liable to get out of order; and, finally, they can be made as cheaply as any others with reversible backs. Preventive of the Decay of Wood. EXPERIMENTS have been carried on in Paris for a long time in the intent of finding out a means of preserving palings, posts, etc., from decay. ~As the result of a five years experience, a paint is recommended which at the same time possesses the advantage of being imper- vious to water. It is composed of fifty parts of tar, forty parts of finely-crushed chalk, five hundred parts of fine, white, hard sand, four parts of linseed oil, one part of the red oxide of copper in its native state, and finally, one part of sulphuric acid. In order to manu- facture the paint from this multiplicity of materials, the tar, chalk, sand, and oil are first heated in an iron kettle; the oxide and sulphuric acid are then added with a good deal of precaution. The mass is then very carefully mixed. It is now ready for use, and must be applied while hot. In coating the timber, a stiff brush is used. If it is found upon using that th~ mixture is not liquid enough, a little more linseed oil should be used. After this paint has cooled and dried; it forms a coating or varnish quite as hard as stoiie. Colorado Manufactures. THE men of the Rocky Mountain regions are im- pressed with the fact that they must not depend upon the East for the various manufactured articles neces- sary to a civilized mode of life. They believe, touching thi~ matter, in the principle of self-maintenance; and acting thereupon, already the whir of the spindles, the blast of the forge, and the blow of the blacksmiths hammer are heard. Although only nine years have passed away since the first house was built within the territorial borders of Colorado, already in that distant domain several factories of lar,,,e capacity are in suc- cessful operation. Denver, the capital city, boasts of but few manufacturing establishments, owing to the fact of its inhabitants having made it the great com- mercial centre or business mart of that mountain country. Nevertheless, it offers great inducements to those contemplating the building up of manufactories in that section, in view of the fact that it possesses a first-class water-power privilege, and, in addition there- to, excellent veins of coal are near at hand. Notwith- standing these natural advantages, the city contains at present only three planing-mills, a soap and candle manufactory, and something like a dozen brick-yards. A twelve-mile ride, however, brings us in full view of the future Lowell of the West, namely, Golden City It is splendidly situated for a manufacturing town. Mines of coal, iron, and copper, deposits of fire and potters clay, gypsum, and other minerals, lie on every hand. Nor has nature left her work but half complete. Through the centre of the town a fine stream of wa- ter, with a fall of sixty feet to the mile, hurries ocean- ward, and offers to the enterprise of the manufacturer a water-power that we hope, at no distant day, xviii set in motion its thousandsyea, its tens and hundreds of thousandso~ ~nsy spindles. With such surroundings, it would have been an anomaly had not the inhabitants of Golden City taken, in part at least, advantage of them. But even as it is, the traveler is somewhat sur- prised that a larger number of works have not already been established. The principal manufactures now carried on are those of pottery ware, paper, pressed and fire brick, leather, plaster of paris, patent tiles, and lime. Without the limits of the town are a number of saw-mills, lime- kilns, etc. Statistics in regard to the manufacturing establishments of Jefferson countyof which Golden City is the county-seatgive the following result: No of Saw-mills 18 Flour and custom mills 4 Distilleries and breweries 2 Tanneries 1 Pottery works8000 gallons per week capacity, 1 Pressed brick-works40 000 per day capacity.. 1 Brick-yards 3 Patent tile-works 2 Plaster of Paris mills 2 Iron foundry 1 Planing-mills 1 Lime.kilns 10 In addition to the above, a woolen mill, a glass manufactory, and a smelting works are either under contract or in course of erection. Other parties have also in contemplation the building of a large machine- shop that would give employment to some three or four hundred hands. It is, however, the opinion of the writer, that the woolen mills of Colorado will eventu- ally yield the largest returns upon investment, and that in view of the very loxv price of the raw mate- rial. The same quality of wool that commands in Boston from 26 to 28 cents per pound is now being sold in Colorado for 16 cents per pound. In this fact, we get an idea of the great profit that may eventually be made in this class of manufactures. Next in im- portance comes the manufacture of iron. One estab .9 J~.2.

The Manufacturer and Builder. of ingredients, is, comparatively speaking, only half useful. He labors as it were oniy to live. As long as he does this, without mental exercise) there will be lit- tle or no advancement made in his industrial pursuits. If the workman, on the other hand, by thought and attention, aims at higher degrees of excellence, his work will very soon bear witness to his more than or- dinary effort. With all the latent powers of the mind quickened and set to work in the study of the arts and sciences, a world, as it were, of wonders will often be brought to view. The man who has in charge the lives of hundreds and the preservation of valuable property as he stands by his steam-boiler and engine on land or at sea, should know something more than to open a valve, use an oil- can, or handle a shovel. The pressure and nature of steam, the strength of materials, the nature of latent heat, economy of fuel, construction, composition of forces, management, and remedies in case of accidents, are subjects which should receive his closest attentioa and study. It is a fact that, at the present day, there are hundreds of men who go through the old system of manufacturing articles of daily consumptionof food especiallywho are totally ignorant of the nature of the ingredients they handle, or the laws which govern, or the chemical cl~nges which take place at the vari- ous stages of the processes employed. For the full development of the mechanic, or any one intended for pursuits connected with the art of construction, they should have a theoretical as well as a practical educa- tion ; they should be taught fundamental rules con- nected with their profession. Every mechanic and artisan, every manufacturer and operative, has, in his respective calling, a field of knowledge which requires constant tilling to bring its hidden treasures to light. It is absurd, says Mr. FAIRBAmN, to talk against theory, as if a knowledge of the exact sciences was a dangerous and a useless attainment; nothing can be more erroneous than this impression, as on close in- spection there is no practice without theory any more than there is no effect without a cause. In the mechan- ical arts, how difficult, precarious, and unsatisfactory are the reasonings of men unacquainted with first principles, and how very often does that deficiency lead them into mal-construction and those errors which a knowledge of science would teach them to avoid. Theory as well as practice, the fundamental princi- ples of cause and effect in all operations, demand alike attention and study from all those engaged in such pursuits. Reversible Seats. IN the general progress that charactdrizes the pre- sent age, and that particularly in the department of practical mechanics, the commonplace but withal very necessary matter of ~eats has not been forgotten. Comfort, convenience, and adaptation as regards physiological considerations of health are the chief ends to be secured in the construction of a seat. The march of invention has pretty nearly swept away the rude, rickety old bench of the country, or village. school-house, with its four legs of unequal lengths, andwoe to the uneasy urchin of eightits surplus- t~e of slivers. Seats, neatly made, with reversible backs which enable the occupant to face either way, are now quite frequently met with, even in the school- houses of the rural districts. They have their place in the lecture-room, the church, and, above all, in our rail- road-cars. But it may be remarked that the reversible seat hitherto in use, however convenient, was without a back. It should be so constructed that an adjust- ment of the seat can be made at the same time with the back. It is very clear that, in order to conduce to comfort, and at the same time to conform to the re- quirements of health, the seat proper shouid be mov- able, so that, when the back is set at any angle, it may be inclined at will downward and backward from the front edge. By such an arrangement, and such only, will the necessary requirements all be fulfilled. The seats represented by the accompanying illustrations combine all these aids to comfort, convenienee, and health. They were patented by W. H. JOEcKEL in the years 1861 and 1868, and are now manufactured by ROBERT PATON, 26 Grove street; New-York City. Fig. 1 is a seat calculated for school-houses, lecture- rooms, and railroad-cars. The sear ~ pivoted on a rod or axis under the seat, connected by a forked rod to an eccentric on the arm of the seat at either end, to which is pivoted, also, the arms supporting the back. As that is lifted and thrown over, the motion of the back compels, by means of the eccentric, a similar motion, although in a less degree, to the seat itself~ tilting it slightly back, and holding it and the back in position by the weight of the person occupy- ing the seat, both back and seat being governed, in their relative positions by the occupant of the seat. Fig. 2 is another form of the seat, presenting cushioned side-pieces for the arms to rest upon in whatever position the back may be. Its connections and action are similar to that intended for the lecture- room, the seat being tilted or inclined with the move- ment of the back. The back is hung on a pivot like a pendulum, and any number of seats may be connected in a line by means of a rod, and the backs reversed simultaneously, one lock fastening them all. They are simple as regards method of construction and operation, nor are they liable to get out of order; and, finally, they can be made as cheaply as any others with reversible backs. Preventive of the Decay of Wood. EXPERIMENTS have been carried on in Paris for a long time in the intent of finding out a means of preserving palings, posts, etc., from decay. ~As the result of a five years experience, a paint is recommended which at the same time possesses the advantage of being imper- vious to water. It is composed of fifty parts of tar, forty parts of finely-crushed chalk, five hundred parts of fine, white, hard sand, four parts of linseed oil, one part of the red oxide of copper in its native state, and finally, one part of sulphuric acid. In order to manu- facture the paint from this multiplicity of materials, the tar, chalk, sand, and oil are first heated in an iron kettle; the oxide and sulphuric acid are then added with a good deal of precaution. The mass is then very carefully mixed. It is now ready for use, and must be applied while hot. In coating the timber, a stiff brush is used. If it is found upon using that th~ mixture is not liquid enough, a little more linseed oil should be used. After this paint has cooled and dried; it forms a coating or varnish quite as hard as stoiie. Colorado Manufactures. THE men of the Rocky Mountain regions are im- pressed with the fact that they must not depend upon the East for the various manufactured articles neces- sary to a civilized mode of life. They believe, touching thi~ matter, in the principle of self-maintenance; and acting thereupon, already the whir of the spindles, the blast of the forge, and the blow of the blacksmiths hammer are heard. Although only nine years have passed away since the first house was built within the territorial borders of Colorado, already in that distant domain several factories of lar,,,e capacity are in suc- cessful operation. Denver, the capital city, boasts of but few manufacturing establishments, owing to the fact of its inhabitants having made it the great com- mercial centre or business mart of that mountain country. Nevertheless, it offers great inducements to those contemplating the building up of manufactories in that section, in view of the fact that it possesses a first-class water-power privilege, and, in addition there- to, excellent veins of coal are near at hand. Notwith- standing these natural advantages, the city contains at present only three planing-mills, a soap and candle manufactory, and something like a dozen brick-yards. A twelve-mile ride, however, brings us in full view of the future Lowell of the West, namely, Golden City It is splendidly situated for a manufacturing town. Mines of coal, iron, and copper, deposits of fire and potters clay, gypsum, and other minerals, lie on every hand. Nor has nature left her work but half complete. Through the centre of the town a fine stream of wa- ter, with a fall of sixty feet to the mile, hurries ocean- ward, and offers to the enterprise of the manufacturer a water-power that we hope, at no distant day, xviii set in motion its thousandsyea, its tens and hundreds of thousandso~ ~nsy spindles. With such surroundings, it would have been an anomaly had not the inhabitants of Golden City taken, in part at least, advantage of them. But even as it is, the traveler is somewhat sur- prised that a larger number of works have not already been established. The principal manufactures now carried on are those of pottery ware, paper, pressed and fire brick, leather, plaster of paris, patent tiles, and lime. Without the limits of the town are a number of saw-mills, lime- kilns, etc. Statistics in regard to the manufacturing establishments of Jefferson countyof which Golden City is the county-seatgive the following result: No of Saw-mills 18 Flour and custom mills 4 Distilleries and breweries 2 Tanneries 1 Pottery works8000 gallons per week capacity, 1 Pressed brick-works40 000 per day capacity.. 1 Brick-yards 3 Patent tile-works 2 Plaster of Paris mills 2 Iron foundry 1 Planing-mills 1 Lime.kilns 10 In addition to the above, a woolen mill, a glass manufactory, and a smelting works are either under contract or in course of erection. Other parties have also in contemplation the building of a large machine- shop that would give employment to some three or four hundred hands. It is, however, the opinion of the writer, that the woolen mills of Colorado will eventu- ally yield the largest returns upon investment, and that in view of the very loxv price of the raw mate- rial. The same quality of wool that commands in Boston from 26 to 28 cents per pound is now being sold in Colorado for 16 cents per pound. In this fact, we get an idea of the great profit that may eventually be made in this class of manufactures. Next in im- portance comes the manufacture of iron. One estab .9 J~.2.

The Manufacturer and Builder. of ingredients, is, comparatively speaking, only half useful. He labors as it were oniy to live. As long as he does this, without mental exercise) there will be lit- tle or no advancement made in his industrial pursuits. If the workman, on the other hand, by thought and attention, aims at higher degrees of excellence, his work will very soon bear witness to his more than or- dinary effort. With all the latent powers of the mind quickened and set to work in the study of the arts and sciences, a world, as it were, of wonders will often be brought to view. The man who has in charge the lives of hundreds and the preservation of valuable property as he stands by his steam-boiler and engine on land or at sea, should know something more than to open a valve, use an oil- can, or handle a shovel. The pressure and nature of steam, the strength of materials, the nature of latent heat, economy of fuel, construction, composition of forces, management, and remedies in case of accidents, are subjects which should receive his closest attentioa and study. It is a fact that, at the present day, there are hundreds of men who go through the old system of manufacturing articles of daily consumptionof food especiallywho are totally ignorant of the nature of the ingredients they handle, or the laws which govern, or the chemical cl~nges which take place at the vari- ous stages of the processes employed. For the full development of the mechanic, or any one intended for pursuits connected with the art of construction, they should have a theoretical as well as a practical educa- tion ; they should be taught fundamental rules con- nected with their profession. Every mechanic and artisan, every manufacturer and operative, has, in his respective calling, a field of knowledge which requires constant tilling to bring its hidden treasures to light. It is absurd, says Mr. FAIRBAmN, to talk against theory, as if a knowledge of the exact sciences was a dangerous and a useless attainment; nothing can be more erroneous than this impression, as on close in- spection there is no practice without theory any more than there is no effect without a cause. In the mechan- ical arts, how difficult, precarious, and unsatisfactory are the reasonings of men unacquainted with first principles, and how very often does that deficiency lead them into mal-construction and those errors which a knowledge of science would teach them to avoid. Theory as well as practice, the fundamental princi- ples of cause and effect in all operations, demand alike attention and study from all those engaged in such pursuits. Reversible Seats. IN the general progress that charactdrizes the pre- sent age, and that particularly in the department of practical mechanics, the commonplace but withal very necessary matter of ~eats has not been forgotten. Comfort, convenience, and adaptation as regards physiological considerations of health are the chief ends to be secured in the construction of a seat. The march of invention has pretty nearly swept away the rude, rickety old bench of the country, or village. school-house, with its four legs of unequal lengths, andwoe to the uneasy urchin of eightits surplus- t~e of slivers. Seats, neatly made, with reversible backs which enable the occupant to face either way, are now quite frequently met with, even in the school- houses of the rural districts. They have their place in the lecture-room, the church, and, above all, in our rail- road-cars. But it may be remarked that the reversible seat hitherto in use, however convenient, was without a back. It should be so constructed that an adjust- ment of the seat can be made at the same time with the back. It is very clear that, in order to conduce to comfort, and at the same time to conform to the re- quirements of health, the seat proper shouid be mov- able, so that, when the back is set at any angle, it may be inclined at will downward and backward from the front edge. By such an arrangement, and such only, will the necessary requirements all be fulfilled. The seats represented by the accompanying illustrations combine all these aids to comfort, convenienee, and health. They were patented by W. H. JOEcKEL in the years 1861 and 1868, and are now manufactured by ROBERT PATON, 26 Grove street; New-York City. Fig. 1 is a seat calculated for school-houses, lecture- rooms, and railroad-cars. The sear ~ pivoted on a rod or axis under the seat, connected by a forked rod to an eccentric on the arm of the seat at either end, to which is pivoted, also, the arms supporting the back. As that is lifted and thrown over, the motion of the back compels, by means of the eccentric, a similar motion, although in a less degree, to the seat itself~ tilting it slightly back, and holding it and the back in position by the weight of the person occupy- ing the seat, both back and seat being governed, in their relative positions by the occupant of the seat. Fig. 2 is another form of the seat, presenting cushioned side-pieces for the arms to rest upon in whatever position the back may be. Its connections and action are similar to that intended for the lecture- room, the seat being tilted or inclined with the move- ment of the back. The back is hung on a pivot like a pendulum, and any number of seats may be connected in a line by means of a rod, and the backs reversed simultaneously, one lock fastening them all. They are simple as regards method of construction and operation, nor are they liable to get out of order; and, finally, they can be made as cheaply as any others with reversible backs. Preventive of the Decay of Wood. EXPERIMENTS have been carried on in Paris for a long time in the intent of finding out a means of preserving palings, posts, etc., from decay. ~As the result of a five years experience, a paint is recommended which at the same time possesses the advantage of being imper- vious to water. It is composed of fifty parts of tar, forty parts of finely-crushed chalk, five hundred parts of fine, white, hard sand, four parts of linseed oil, one part of the red oxide of copper in its native state, and finally, one part of sulphuric acid. In order to manu- facture the paint from this multiplicity of materials, the tar, chalk, sand, and oil are first heated in an iron kettle; the oxide and sulphuric acid are then added with a good deal of precaution. The mass is then very carefully mixed. It is now ready for use, and must be applied while hot. In coating the timber, a stiff brush is used. If it is found upon using that th~ mixture is not liquid enough, a little more linseed oil should be used. After this paint has cooled and dried; it forms a coating or varnish quite as hard as stoiie. Colorado Manufactures. THE men of the Rocky Mountain regions are im- pressed with the fact that they must not depend upon the East for the various manufactured articles neces- sary to a civilized mode of life. They believe, touching thi~ matter, in the principle of self-maintenance; and acting thereupon, already the whir of the spindles, the blast of the forge, and the blow of the blacksmiths hammer are heard. Although only nine years have passed away since the first house was built within the territorial borders of Colorado, already in that distant domain several factories of lar,,,e capacity are in suc- cessful operation. Denver, the capital city, boasts of but few manufacturing establishments, owing to the fact of its inhabitants having made it the great com- mercial centre or business mart of that mountain country. Nevertheless, it offers great inducements to those contemplating the building up of manufactories in that section, in view of the fact that it possesses a first-class water-power privilege, and, in addition there- to, excellent veins of coal are near at hand. Notwith- standing these natural advantages, the city contains at present only three planing-mills, a soap and candle manufactory, and something like a dozen brick-yards. A twelve-mile ride, however, brings us in full view of the future Lowell of the West, namely, Golden City It is splendidly situated for a manufacturing town. Mines of coal, iron, and copper, deposits of fire and potters clay, gypsum, and other minerals, lie on every hand. Nor has nature left her work but half complete. Through the centre of the town a fine stream of wa- ter, with a fall of sixty feet to the mile, hurries ocean- ward, and offers to the enterprise of the manufacturer a water-power that we hope, at no distant day, xviii set in motion its thousandsyea, its tens and hundreds of thousandso~ ~nsy spindles. With such surroundings, it would have been an anomaly had not the inhabitants of Golden City taken, in part at least, advantage of them. But even as it is, the traveler is somewhat sur- prised that a larger number of works have not already been established. The principal manufactures now carried on are those of pottery ware, paper, pressed and fire brick, leather, plaster of paris, patent tiles, and lime. Without the limits of the town are a number of saw-mills, lime- kilns, etc. Statistics in regard to the manufacturing establishments of Jefferson countyof which Golden City is the county-seatgive the following result: No of Saw-mills 18 Flour and custom mills 4 Distilleries and breweries 2 Tanneries 1 Pottery works8000 gallons per week capacity, 1 Pressed brick-works40 000 per day capacity.. 1 Brick-yards 3 Patent tile-works 2 Plaster of Paris mills 2 Iron foundry 1 Planing-mills 1 Lime.kilns 10 In addition to the above, a woolen mill, a glass manufactory, and a smelting works are either under contract or in course of erection. Other parties have also in contemplation the building of a large machine- shop that would give employment to some three or four hundred hands. It is, however, the opinion of the writer, that the woolen mills of Colorado will eventu- ally yield the largest returns upon investment, and that in view of the very loxv price of the raw mate- rial. The same quality of wool that commands in Boston from 26 to 28 cents per pound is now being sold in Colorado for 16 cents per pound. In this fact, we get an idea of the great profit that may eventually be made in this class of manufactures. Next in im- portance comes the manufacture of iron. One estab .9 J~.2.

The Manufacturer and Builder. of ingredients, is, comparatively speaking, only half useful. He labors as it were oniy to live. As long as he does this, without mental exercise) there will be lit- tle or no advancement made in his industrial pursuits. If the workman, on the other hand, by thought and attention, aims at higher degrees of excellence, his work will very soon bear witness to his more than or- dinary effort. With all the latent powers of the mind quickened and set to work in the study of the arts and sciences, a world, as it were, of wonders will often be brought to view. The man who has in charge the lives of hundreds and the preservation of valuable property as he stands by his steam-boiler and engine on land or at sea, should know something more than to open a valve, use an oil- can, or handle a shovel. The pressure and nature of steam, the strength of materials, the nature of latent heat, economy of fuel, construction, composition of forces, management, and remedies in case of accidents, are subjects which should receive his closest attentioa and study. It is a fact that, at the present day, there are hundreds of men who go through the old system of manufacturing articles of daily consumptionof food especiallywho are totally ignorant of the nature of the ingredients they handle, or the laws which govern, or the chemical cl~nges which take place at the vari- ous stages of the processes employed. For the full development of the mechanic, or any one intended for pursuits connected with the art of construction, they should have a theoretical as well as a practical educa- tion ; they should be taught fundamental rules con- nected with their profession. Every mechanic and artisan, every manufacturer and operative, has, in his respective calling, a field of knowledge which requires constant tilling to bring its hidden treasures to light. It is absurd, says Mr. FAIRBAmN, to talk against theory, as if a knowledge of the exact sciences was a dangerous and a useless attainment; nothing can be more erroneous than this impression, as on close in- spection there is no practice without theory any more than there is no effect without a cause. In the mechan- ical arts, how difficult, precarious, and unsatisfactory are the reasonings of men unacquainted with first principles, and how very often does that deficiency lead them into mal-construction and those errors which a knowledge of science would teach them to avoid. Theory as well as practice, the fundamental princi- ples of cause and effect in all operations, demand alike attention and study from all those engaged in such pursuits. Reversible Seats. IN the general progress that charactdrizes the pre- sent age, and that particularly in the department of practical mechanics, the commonplace but withal very necessary matter of ~eats has not been forgotten. Comfort, convenience, and adaptation as regards physiological considerations of health are the chief ends to be secured in the construction of a seat. The march of invention has pretty nearly swept away the rude, rickety old bench of the country, or village. school-house, with its four legs of unequal lengths, andwoe to the uneasy urchin of eightits surplus- t~e of slivers. Seats, neatly made, with reversible backs which enable the occupant to face either way, are now quite frequently met with, even in the school- houses of the rural districts. They have their place in the lecture-room, the church, and, above all, in our rail- road-cars. But it may be remarked that the reversible seat hitherto in use, however convenient, was without a back. It should be so constructed that an adjust- ment of the seat can be made at the same time with the back. It is very clear that, in order to conduce to comfort, and at the same time to conform to the re- quirements of health, the seat proper shouid be mov- able, so that, when the back is set at any angle, it may be inclined at will downward and backward from the front edge. By such an arrangement, and such only, will the necessary requirements all be fulfilled. The seats represented by the accompanying illustrations combine all these aids to comfort, convenienee, and health. They were patented by W. H. JOEcKEL in the years 1861 and 1868, and are now manufactured by ROBERT PATON, 26 Grove street; New-York City. Fig. 1 is a seat calculated for school-houses, lecture- rooms, and railroad-cars. The sear ~ pivoted on a rod or axis under the seat, connected by a forked rod to an eccentric on the arm of the seat at either end, to which is pivoted, also, the arms supporting the back. As that is lifted and thrown over, the motion of the back compels, by means of the eccentric, a similar motion, although in a less degree, to the seat itself~ tilting it slightly back, and holding it and the back in position by the weight of the person occupy- ing the seat, both back and seat being governed, in their relative positions by the occupant of the seat. Fig. 2 is another form of the seat, presenting cushioned side-pieces for the arms to rest upon in whatever position the back may be. Its connections and action are similar to that intended for the lecture- room, the seat being tilted or inclined with the move- ment of the back. The back is hung on a pivot like a pendulum, and any number of seats may be connected in a line by means of a rod, and the backs reversed simultaneously, one lock fastening them all. They are simple as regards method of construction and operation, nor are they liable to get out of order; and, finally, they can be made as cheaply as any others with reversible backs. Preventive of the Decay of Wood. EXPERIMENTS have been carried on in Paris for a long time in the intent of finding out a means of preserving palings, posts, etc., from decay. ~As the result of a five years experience, a paint is recommended which at the same time possesses the advantage of being imper- vious to water. It is composed of fifty parts of tar, forty parts of finely-crushed chalk, five hundred parts of fine, white, hard sand, four parts of linseed oil, one part of the red oxide of copper in its native state, and finally, one part of sulphuric acid. In order to manu- facture the paint from this multiplicity of materials, the tar, chalk, sand, and oil are first heated in an iron kettle; the oxide and sulphuric acid are then added with a good deal of precaution. The mass is then very carefully mixed. It is now ready for use, and must be applied while hot. In coating the timber, a stiff brush is used. If it is found upon using that th~ mixture is not liquid enough, a little more linseed oil should be used. After this paint has cooled and dried; it forms a coating or varnish quite as hard as stoiie. Colorado Manufactures. THE men of the Rocky Mountain regions are im- pressed with the fact that they must not depend upon the East for the various manufactured articles neces- sary to a civilized mode of life. They believe, touching thi~ matter, in the principle of self-maintenance; and acting thereupon, already the whir of the spindles, the blast of the forge, and the blow of the blacksmiths hammer are heard. Although only nine years have passed away since the first house was built within the territorial borders of Colorado, already in that distant domain several factories of lar,,,e capacity are in suc- cessful operation. Denver, the capital city, boasts of but few manufacturing establishments, owing to the fact of its inhabitants having made it the great com- mercial centre or business mart of that mountain country. Nevertheless, it offers great inducements to those contemplating the building up of manufactories in that section, in view of the fact that it possesses a first-class water-power privilege, and, in addition there- to, excellent veins of coal are near at hand. Notwith- standing these natural advantages, the city contains at present only three planing-mills, a soap and candle manufactory, and something like a dozen brick-yards. A twelve-mile ride, however, brings us in full view of the future Lowell of the West, namely, Golden City It is splendidly situated for a manufacturing town. Mines of coal, iron, and copper, deposits of fire and potters clay, gypsum, and other minerals, lie on every hand. Nor has nature left her work but half complete. Through the centre of the town a fine stream of wa- ter, with a fall of sixty feet to the mile, hurries ocean- ward, and offers to the enterprise of the manufacturer a water-power that we hope, at no distant day, xviii set in motion its thousandsyea, its tens and hundreds of thousandso~ ~nsy spindles. With such surroundings, it would have been an anomaly had not the inhabitants of Golden City taken, in part at least, advantage of them. But even as it is, the traveler is somewhat sur- prised that a larger number of works have not already been established. The principal manufactures now carried on are those of pottery ware, paper, pressed and fire brick, leather, plaster of paris, patent tiles, and lime. Without the limits of the town are a number of saw-mills, lime- kilns, etc. Statistics in regard to the manufacturing establishments of Jefferson countyof which Golden City is the county-seatgive the following result: No of Saw-mills 18 Flour and custom mills 4 Distilleries and breweries 2 Tanneries 1 Pottery works8000 gallons per week capacity, 1 Pressed brick-works40 000 per day capacity.. 1 Brick-yards 3 Patent tile-works 2 Plaster of Paris mills 2 Iron foundry 1 Planing-mills 1 Lime.kilns 10 In addition to the above, a woolen mill, a glass manufactory, and a smelting works are either under contract or in course of erection. Other parties have also in contemplation the building of a large machine- shop that would give employment to some three or four hundred hands. It is, however, the opinion of the writer, that the woolen mills of Colorado will eventu- ally yield the largest returns upon investment, and that in view of the very loxv price of the raw mate- rial. The same quality of wool that commands in Boston from 26 to 28 cents per pound is now being sold in Colorado for 16 cents per pound. In this fact, we get an idea of the great profit that may eventually be made in this class of manufactures. Next in im- portance comes the manufacture of iron. One estab .9 J~.2. The Manufacturer and ]3uilder. lishment for its manufacture is already under way at Belmont, soms sixteen miles from Golden City. The success is so great that the proprietor intends exten- sive additions the coming spring. The price of skilled labor in Colorado ranges about as follows: Carpenters, 5 to $7 per day; bricklayers, $5 to $7 per day; blacksmiths, $4.50 to $7.50 per day; tanners, $4.50 per day; machinists, $4.50 to $6 per day; printers, 62~ to 70 cents per thousand ems, or 29 per week; foremen, $35 to 40 per week; engineers, $4 to $5 per day; miners, $3 to $4.50 per day; brick-moulders, $5 per day. Common laborers receive 3 per day, or from 45 to $60 per month, and board; teamsters, from $40 to $60 per month, and board; farm hands, from $35 to $45 per month, and board, while hod-carriers are paid 3.50 per day. The work- men of other trades receive a proportionate compensa- tion. There are plenty of clerks, salesmen, and tbe like in the territory, the supply exceeding the dem~nd. There is a large representation of civil engineers, law- yers, and doctors among the inhabitants; but many of the latter find it hard work to get a living at their pro- fession, and often turn their attention to mining. Board ranges from $6 to 12 per week in hotels and boarding-houses, though where a number of individu- als unite together and board themselves, they are able to live comfortably for about $4 per week. We may hereafter be able to speak somewhat iu detail of the pottery works and other manufkcturing establish- inents of the territory. Chemical Engineering. TIrE time has been, and is even now but slowly lapsing into the darkness of the past, when men who delve for knowledge beaeath the surface of things were pitied or scorned as poetic dreamers, or as grown-up children, by the mass of mankind, and es- pecially by that class who call themselves, and sometimes justly, practical men. But now many of these children who have grown up in the chase of butterflies and the like are recognized and honored as benefactors of the race. At present, however, we have more to do with another class of the children of science who have been looked upon as frittering away the precious time that practical men spend in their moneyed avocations. But the time has almost come when few will sneer at the statement that more is to be learned, of a rietly practical kind, in relation t& the laws governing the strength and durability of materials an accurate understanding of which is so essential to the xveal of manfrom the investigations of scientists, than from all the experiments with bricks and mor- tar since the time of the building of the Tower of Babel. We may reasonably hope that the thue is near at hand when that powerful word-weapon of the practical man, the Gui boao ? xviii cease to tyrannize over the world at large, or discourage the seeker aftei the hid- den truths of nature. However, it may be assumed that there will be found, among the readers of this periodical, an impoi- taut and leading class of the community, now rapidly growing in numbers, who will feel no surprise at the assertion that tbe path of practicd~ ctiscovery, which is to lead mankind to the mastery and the intelligent use of materials, lies through the chemical labora- tory. The theme is one on xvhich a treatise of some magnitude might even noxv be written, and which soon will rank as a separate specialty. We believe that the practical engineer who has passed through a thorough course of laboratory training will soon hereafter find himself, casteris paribal, ranking high above those who have merely traveled, in the old beaten paths. Still, however, we must admit the sub- ject is yet very macli in embryo. As in mechanism the realization of new combinations and inventions, and even the introduction of ne~v materials or tools, requires continued invention and construction of nexv 8ubsidiary tools and machines for combining, handling, and m~mipuhating these, so in science all progress once discovered, its practical application is but a mat- ter of time, and nowadays frequently of a very short time. The shrexvd engineer xviii therefore prepare himself for what is to come, by maintaining a. thor- ough familiarity with those discoveries made in the laboratory that bear in any way upon the practice of his profession. In an article like tLi~, space will admit only of a few brief citations of the more prominent illustrations of the facts that point to the near est~bhishnxent of the new specialty; for which the name Chemical Engi- neerinois proposed. In future numbers of this paper, tile subject will probably be resumed more in detail. Tile mere chemical composition and analysis of materials is in itself often of minor importance, and only of subsidiary value. The late discoveries of scientists as regards the molecular structure and tex- ture of materials, and thechanges which these under- go, promise results of great direct importance to tile engineer and the architect. The fact that axles, rails, and springs give xvay, bridges break down, buildings fall, and boilers and can- non burst, and that, too, often without any assignable fault in their original construction, belongs to a range of phenomena wlliell are now calling for the active investigation of chemists, and results of thu utmost importance are already foreshadowed. In some of these cases, it ilas been long known that certain changes are found to have taken place in tile internal texture of tile fractured material. Until recently, it ilas been generally supposed that tilese cllanges were of a mere- ly mechanical nature. At all events, fexv persons ilave referred these results to causes of a strictly ellemical cilaracter. Investigations now point to very different conclusions. Since tIle experiments of WAnr~ und RODMAN, it has been obvious to cilemists that tile l)ursting of cannon is most frequently due to the corrosion, both superficially and in its inmost substance, even to the extent of a coniplete iloneycombing, especially in tile neigllborllood of tile vent of tile metal, by tile injec- tioll into its pores of the vapors of sulphur and sul- phide of potassium. Cllemist.s Ilave long knoxvn that pure distilled xvater will dissolve ferreous ilydrate, and in tile presence of free oxygen xviii q& ickly take up metallic iron into this form of sobltion. Hence, in a steam boiler, such por- tions of the internal surfaces as are subj ect to tile con- densation upon tilem of distilled water from tile steam, in an atmosphere xvhich alxvays contains free oxygen that had been dissolved in the water, and frequently under heat and pressure, must be botil corroded superficially and disi1lte~rated internally. In tills we have the cause of many of our most fearful dis- asters. How many lives ilave been lost by tile breaking of axles, springs, rails, etc., xvhicll might have been saved, ilad we known 110w to protect these completely from tile corroding action of tile oxygen of tile air, introduced in aqueous solution into tlleir pores and flaws, none can tell. The nexv experiment of steel rails, ill a clinlate hike ours, whose intense cold is known to de- stroy all tile viscosity of steel and heave oPly its brittle- ness, is contenlplated witil foreboding. Tills latter ease leads to tile suggestion that no question requires tile atteiltioll of tile inxestigator more tilan tilose con- ilected xvithl tile different kinds of consistence of mat- ter, tile influence of. various agents in modifying tile sanle, and tile ulodes of producing and conserving any desired fornl of consistence. GRAHAM ilas generalized all consistence under two ileads : tile crystalloid and colloid. It teems clear to us tilat to tilese must be added tile viscous or viscoid con~istence, if not still otiler distinct species. The effects of natural and otiler chemical agents upon the various forms of vulcanized rubber and conlpounds thereof now in use are undergoing investi- gation by one of tile most eminent of our American cilelnists, xvitll results of tile ilighest novelty and im- portance, in due time to be laid before tile public. must likewise be gradual and cumulative. All I Another great field for tile chemical engineerto ilimlall experiellee proves, ilevertileless, tilat tile law which much attentioll ilas been already given, but ilas by 110 means begun to yield its full fruitis in tile ~reservatioil froul decay, from fire, and otiler oestructive no-encies, of suell substances as stone, wood, and otiler nlateriala used in building and in tile construction of veilicles. It is clear that iron, as a ulaterial for tilese purpdses, is continually disappointing tile sailguille expectations of tilose wile do not understand xvell its inllerent defects ; and xve believe tile time will 50011 come Ivilen wood, so prepared chemically as to be in- combustible, indestructible, and a perfect non-conduc- tor of ileat, xviii be tile alillost universal material used 111 tile construction of buildillgs and vellicles, ex- cept of course tile nlachinery of the hatter. We will only allude, ill closilIg tills article, to tile re- markable application, of whiell we Ilave lately ileard, of a laboratory instrunlent, an electro-nlagnet, to the de- tection of fiaxvs and imperfections in the interior of a n~ass of iron or steel. The New Art of Fresco-Painting. Ti-ix art of stereocilromy must be considered as in- volving an entirely new mode of creating durable pictures upon walls, inasalucil as a new binding mate- rial is applied, whicil differs from any employed in tile usual nlodes of mural painting. By tilis binding nlate- rial, xvhlicil IS tile soluble glass of cofllmerce, tile colors become, as it xvere, silicifled; and pictures executed in this way distinguish themselves by a certain fresilness and a power of resisting atalospheric influences Ivilicil ordinary frescoes do not possess. In giving an account of this interesting mode of paintillg, xve silail confine ourselves to a general out- line of the method bywhicil KAULBACH, tile celebrated artist of Municil, and ECHTEII, ilave executed, in the nexv museun~ at Berlin, four large pictures, whicil are generally acknoxvledged to exilibit a great advance in tile art of nIural painting. Tile wall to be painted is first coated Witil a layer of ordinary hinle-nlortar, in order to equalize its unevenness. The sand employed, wilicil may be either silicious or calcareous, must l)e of even grain and xvell washed beforehand. Lime nlust be sparingly employed, so as to render the cement ratiler poor tilall otilerxvise. In tills and ill all the subsequemlt operations, pure rain-water lIllist be used. Tile plaster, tilus prepared, must be well dried and exposed to tile air for several days, so as to become en- tirely carbonated. Caustic 1mb would decompose tile soluble glass. Fucirs, tile inventor of stereoeilromy, reconlillends tile uloistening of the xvall several times Ivitil a solution of carbonate of amnlonia, so as to acce- lerate tile saturatioll of tlle lime. Wilen dry, it is xvaslled over several tinles xvitil a llloderatehy diluted solution of the so-called double xvater-glass, allow. ilIg it to dry each thlle. Tile ground being tilils prepared, the upper layer may be seen after added. It consists, like tile loxver one, of a lime-mortar, and is spread in the tilickness of about 0110 tentll of an mdl. Tile sand eIllployed ulust be Ivell Ivasiled, and of a graill not exceeding a certain size. Very fine powder must be rejected; and for tills reason it is best to pass it tiliougil a sieve. A ror~ll grain is ratiler advantageous; KAULBACH says it ougilt to feel like a rasp. For a picture to be viewed at a great distance, a coarser grain is required than for one designed for closer inspection. When tile coating is perfectly dry, i~ is sometimes rubbed witil a sllarp sandstone, In order to remove tIle layer formed of carbonate of hale. It is better, 110w- ever, to accomphisil tills by means of diluted phospiloric acid. Tile pilospilate of 1mb thus foraled b;nds tile soluble glass, a solutioll of wilicil, Ivhlell tile coat. .s d:y, is spread over tile surface. The same is dii :~ed w~.il its equal bulk of water, and tile operation is twtee re- peated. Too much xvater-glass prevents the ground froma taking tile colors. Tile ground being thus pre- pared, the painting n~ay be at once proceeded with; sonle delay, ilolvever, increases tile capacity for ab- sorption. The colors to be used must be ground with pure water, (we xviii speak of tileir preparation in a 10

The Manufacturer and ]3uilder. lishment for its manufacture is already under way at Belmont, soms sixteen miles from Golden City. The success is so great that the proprietor intends exten- sive additions the coming spring. The price of skilled labor in Colorado ranges about as follows: Carpenters, 5 to $7 per day; bricklayers, $5 to $7 per day; blacksmiths, $4.50 to $7.50 per day; tanners, $4.50 per day; machinists, $4.50 to $6 per day; printers, 62~ to 70 cents per thousand ems, or 29 per week; foremen, $35 to 40 per week; engineers, $4 to $5 per day; miners, $3 to $4.50 per day; brick-moulders, $5 per day. Common laborers receive 3 per day, or from 45 to $60 per month, and board; teamsters, from $40 to $60 per month, and board; farm hands, from $35 to $45 per month, and board, while hod-carriers are paid 3.50 per day. The work- men of other trades receive a proportionate compensa- tion. There are plenty of clerks, salesmen, and tbe like in the territory, the supply exceeding the dem~nd. There is a large representation of civil engineers, law- yers, and doctors among the inhabitants; but many of the latter find it hard work to get a living at their pro- fession, and often turn their attention to mining. Board ranges from $6 to 12 per week in hotels and boarding-houses, though where a number of individu- als unite together and board themselves, they are able to live comfortably for about $4 per week. We may hereafter be able to speak somewhat iu detail of the pottery works and other manufkcturing establish- inents of the territory. Chemical Engineering. TIrE time has been, and is even now but slowly lapsing into the darkness of the past, when men who delve for knowledge beaeath the surface of things were pitied or scorned as poetic dreamers, or as grown-up children, by the mass of mankind, and es- pecially by that class who call themselves, and sometimes justly, practical men. But now many of these children who have grown up in the chase of butterflies and the like are recognized and honored as benefactors of the race. At present, however, we have more to do with another class of the children of science who have been looked upon as frittering away the precious time that practical men spend in their moneyed avocations. But the time has almost come when few will sneer at the statement that more is to be learned, of a rietly practical kind, in relation t& the laws governing the strength and durability of materials an accurate understanding of which is so essential to the xveal of manfrom the investigations of scientists, than from all the experiments with bricks and mor- tar since the time of the building of the Tower of Babel. We may reasonably hope that the thue is near at hand when that powerful word-weapon of the practical man, the Gui boao ? xviii cease to tyrannize over the world at large, or discourage the seeker aftei the hid- den truths of nature. However, it may be assumed that there will be found, among the readers of this periodical, an impoi- taut and leading class of the community, now rapidly growing in numbers, who will feel no surprise at the assertion that tbe path of practicd~ ctiscovery, which is to lead mankind to the mastery and the intelligent use of materials, lies through the chemical labora- tory. The theme is one on xvhich a treatise of some magnitude might even noxv be written, and which soon will rank as a separate specialty. We believe that the practical engineer who has passed through a thorough course of laboratory training will soon hereafter find himself, casteris paribal, ranking high above those who have merely traveled, in the old beaten paths. Still, however, we must admit the sub- ject is yet very macli in embryo. As in mechanism the realization of new combinations and inventions, and even the introduction of ne~v materials or tools, requires continued invention and construction of nexv 8ubsidiary tools and machines for combining, handling, and m~mipuhating these, so in science all progress once discovered, its practical application is but a mat- ter of time, and nowadays frequently of a very short time. The shrexvd engineer xviii therefore prepare himself for what is to come, by maintaining a. thor- ough familiarity with those discoveries made in the laboratory that bear in any way upon the practice of his profession. In an article like tLi~, space will admit only of a few brief citations of the more prominent illustrations of the facts that point to the near est~bhishnxent of the new specialty; for which the name Chemical Engi- neerinois proposed. In future numbers of this paper, tile subject will probably be resumed more in detail. Tile mere chemical composition and analysis of materials is in itself often of minor importance, and only of subsidiary value. The late discoveries of scientists as regards the molecular structure and tex- ture of materials, and thechanges which these under- go, promise results of great direct importance to tile engineer and the architect. The fact that axles, rails, and springs give xvay, bridges break down, buildings fall, and boilers and can- non burst, and that, too, often without any assignable fault in their original construction, belongs to a range of phenomena wlliell are now calling for the active investigation of chemists, and results of thu utmost importance are already foreshadowed. In some of these cases, it ilas been long known that certain changes are found to have taken place in tile internal texture of tile fractured material. Until recently, it ilas been generally supposed that tilese cllanges were of a mere- ly mechanical nature. At all events, fexv persons ilave referred these results to causes of a strictly ellemical cilaracter. Investigations now point to very different conclusions. Since tIle experiments of WAnr~ und RODMAN, it has been obvious to cilemists that tile l)ursting of cannon is most frequently due to the corrosion, both superficially and in its inmost substance, even to the extent of a coniplete iloneycombing, especially in tile neigllborllood of tile vent of tile metal, by tile injec- tioll into its pores of the vapors of sulphur and sul- phide of potassium. Cllemist.s Ilave long knoxvn that pure distilled xvater will dissolve ferreous ilydrate, and in tile presence of free oxygen xviii q& ickly take up metallic iron into this form of sobltion. Hence, in a steam boiler, such por- tions of the internal surfaces as are subj ect to tile con- densation upon tilem of distilled water from tile steam, in an atmosphere xvhich alxvays contains free oxygen that had been dissolved in the water, and frequently under heat and pressure, must be botil corroded superficially and disi1lte~rated internally. In tills we have the cause of many of our most fearful dis- asters. How many lives ilave been lost by tile breaking of axles, springs, rails, etc., xvhicll might have been saved, ilad we known 110w to protect these completely from tile corroding action of tile oxygen of tile air, introduced in aqueous solution into tlleir pores and flaws, none can tell. The nexv experiment of steel rails, ill a clinlate hike ours, whose intense cold is known to de- stroy all tile viscosity of steel and heave oPly its brittle- ness, is contenlplated witil foreboding. Tills latter ease leads to tile suggestion that no question requires tile atteiltioll of tile inxestigator more tilan tilose con- ilected xvithl tile different kinds of consistence of mat- ter, tile influence of. various agents in modifying tile sanle, and tile ulodes of producing and conserving any desired fornl of consistence. GRAHAM ilas generalized all consistence under two ileads : tile crystalloid and colloid. It teems clear to us tilat to tilese must be added tile viscous or viscoid con~istence, if not still otiler distinct species. The effects of natural and otiler chemical agents upon the various forms of vulcanized rubber and conlpounds thereof now in use are undergoing investi- gation by one of tile most eminent of our American cilelnists, xvitll results of tile ilighest novelty and im- portance, in due time to be laid before tile public. must likewise be gradual and cumulative. All I Another great field for tile chemical engineerto ilimlall experiellee proves, ilevertileless, tilat tile law which much attentioll ilas been already given, but ilas by 110 means begun to yield its full fruitis in tile ~reservatioil froul decay, from fire, and otiler oestructive no-encies, of suell substances as stone, wood, and otiler nlateriala used in building and in tile construction of veilicles. It is clear that iron, as a ulaterial for tilese purpdses, is continually disappointing tile sailguille expectations of tilose wile do not understand xvell its inllerent defects ; and xve believe tile time will 50011 come Ivilen wood, so prepared chemically as to be in- combustible, indestructible, and a perfect non-conduc- tor of ileat, xviii be tile alillost universal material used 111 tile construction of buildillgs and vellicles, ex- cept of course tile nlachinery of the hatter. We will only allude, ill closilIg tills article, to tile re- markable application, of whiell we Ilave lately ileard, of a laboratory instrunlent, an electro-nlagnet, to the de- tection of fiaxvs and imperfections in the interior of a n~ass of iron or steel. The New Art of Fresco-Painting. Ti-ix art of stereocilromy must be considered as in- volving an entirely new mode of creating durable pictures upon walls, inasalucil as a new binding mate- rial is applied, whicil differs from any employed in tile usual nlodes of mural painting. By tilis binding nlate- rial, xvhlicil IS tile soluble glass of cofllmerce, tile colors become, as it xvere, silicifled; and pictures executed in this way distinguish themselves by a certain fresilness and a power of resisting atalospheric influences Ivilicil ordinary frescoes do not possess. In giving an account of this interesting mode of paintillg, xve silail confine ourselves to a general out- line of the method bywhicil KAULBACH, tile celebrated artist of Municil, and ECHTEII, ilave executed, in the nexv museun~ at Berlin, four large pictures, whicil are generally acknoxvledged to exilibit a great advance in tile art of nIural painting. Tile wall to be painted is first coated Witil a layer of ordinary hinle-nlortar, in order to equalize its unevenness. The sand employed, wilicil may be either silicious or calcareous, must l)e of even grain and xvell washed beforehand. Lime nlust be sparingly employed, so as to render the cement ratiler poor tilall otilerxvise. In tills and ill all the subsequemlt operations, pure rain-water lIllist be used. Tile plaster, tilus prepared, must be well dried and exposed to tile air for several days, so as to become en- tirely carbonated. Caustic 1mb would decompose tile soluble glass. Fucirs, tile inventor of stereoeilromy, reconlillends tile uloistening of the xvall several times Ivitil a solution of carbonate of amnlonia, so as to acce- lerate tile saturatioll of tlle lime. Wilen dry, it is xvaslled over several tinles xvitil a llloderatehy diluted solution of the so-called double xvater-glass, allow. ilIg it to dry each thlle. Tile ground being tilils prepared, the upper layer may be seen after added. It consists, like tile loxver one, of a lime-mortar, and is spread in the tilickness of about 0110 tentll of an mdl. Tile sand eIllployed ulust be Ivell Ivasiled, and of a graill not exceeding a certain size. Very fine powder must be rejected; and for tills reason it is best to pass it tiliougil a sieve. A ror~ll grain is ratiler advantageous; KAULBACH says it ougilt to feel like a rasp. For a picture to be viewed at a great distance, a coarser grain is required than for one designed for closer inspection. When tile coating is perfectly dry, i~ is sometimes rubbed witil a sllarp sandstone, In order to remove tIle layer formed of carbonate of hale. It is better, 110w- ever, to accomphisil tills by means of diluted phospiloric acid. Tile pilospilate of 1mb thus foraled b;nds tile soluble glass, a solutioll of wilicil, Ivhlell tile coat. .s d:y, is spread over tile surface. The same is dii :~ed w~.il its equal bulk of water, and tile operation is twtee re- peated. Too much xvater-glass prevents the ground froma taking tile colors. Tile ground being thus pre- pared, the painting n~ay be at once proceeded with; sonle delay, ilolvever, increases tile capacity for ab- sorption. The colors to be used must be ground with pure water, (we xviii speak of tileir preparation in a 10

The Manufacturer and ]3uilder. lishment for its manufacture is already under way at Belmont, soms sixteen miles from Golden City. The success is so great that the proprietor intends exten- sive additions the coming spring. The price of skilled labor in Colorado ranges about as follows: Carpenters, 5 to $7 per day; bricklayers, $5 to $7 per day; blacksmiths, $4.50 to $7.50 per day; tanners, $4.50 per day; machinists, $4.50 to $6 per day; printers, 62~ to 70 cents per thousand ems, or 29 per week; foremen, $35 to 40 per week; engineers, $4 to $5 per day; miners, $3 to $4.50 per day; brick-moulders, $5 per day. Common laborers receive 3 per day, or from 45 to $60 per month, and board; teamsters, from $40 to $60 per month, and board; farm hands, from $35 to $45 per month, and board, while hod-carriers are paid 3.50 per day. The work- men of other trades receive a proportionate compensa- tion. There are plenty of clerks, salesmen, and tbe like in the territory, the supply exceeding the dem~nd. There is a large representation of civil engineers, law- yers, and doctors among the inhabitants; but many of the latter find it hard work to get a living at their pro- fession, and often turn their attention to mining. Board ranges from $6 to 12 per week in hotels and boarding-houses, though where a number of individu- als unite together and board themselves, they are able to live comfortably for about $4 per week. We may hereafter be able to speak somewhat iu detail of the pottery works and other manufkcturing establish- inents of the territory. Chemical Engineering. TIrE time has been, and is even now but slowly lapsing into the darkness of the past, when men who delve for knowledge beaeath the surface of things were pitied or scorned as poetic dreamers, or as grown-up children, by the mass of mankind, and es- pecially by that class who call themselves, and sometimes justly, practical men. But now many of these children who have grown up in the chase of butterflies and the like are recognized and honored as benefactors of the race. At present, however, we have more to do with another class of the children of science who have been looked upon as frittering away the precious time that practical men spend in their moneyed avocations. But the time has almost come when few will sneer at the statement that more is to be learned, of a rietly practical kind, in relation t& the laws governing the strength and durability of materials an accurate understanding of which is so essential to the xveal of manfrom the investigations of scientists, than from all the experiments with bricks and mor- tar since the time of the building of the Tower of Babel. We may reasonably hope that the thue is near at hand when that powerful word-weapon of the practical man, the Gui boao ? xviii cease to tyrannize over the world at large, or discourage the seeker aftei the hid- den truths of nature. However, it may be assumed that there will be found, among the readers of this periodical, an impoi- taut and leading class of the community, now rapidly growing in numbers, who will feel no surprise at the assertion that tbe path of practicd~ ctiscovery, which is to lead mankind to the mastery and the intelligent use of materials, lies through the chemical labora- tory. The theme is one on xvhich a treatise of some magnitude might even noxv be written, and which soon will rank as a separate specialty. We believe that the practical engineer who has passed through a thorough course of laboratory training will soon hereafter find himself, casteris paribal, ranking high above those who have merely traveled, in the old beaten paths. Still, however, we must admit the sub- ject is yet very macli in embryo. As in mechanism the realization of new combinations and inventions, and even the introduction of ne~v materials or tools, requires continued invention and construction of nexv 8ubsidiary tools and machines for combining, handling, and m~mipuhating these, so in science all progress once discovered, its practical application is but a mat- ter of time, and nowadays frequently of a very short time. The shrexvd engineer xviii therefore prepare himself for what is to come, by maintaining a. thor- ough familiarity with those discoveries made in the laboratory that bear in any way upon the practice of his profession. In an article like tLi~, space will admit only of a few brief citations of the more prominent illustrations of the facts that point to the near est~bhishnxent of the new specialty; for which the name Chemical Engi- neerinois proposed. In future numbers of this paper, tile subject will probably be resumed more in detail. Tile mere chemical composition and analysis of materials is in itself often of minor importance, and only of subsidiary value. The late discoveries of scientists as regards the molecular structure and tex- ture of materials, and thechanges which these under- go, promise results of great direct importance to tile engineer and the architect. The fact that axles, rails, and springs give xvay, bridges break down, buildings fall, and boilers and can- non burst, and that, too, often without any assignable fault in their original construction, belongs to a range of phenomena wlliell are now calling for the active investigation of chemists, and results of thu utmost importance are already foreshadowed. In some of these cases, it ilas been long known that certain changes are found to have taken place in tile internal texture of tile fractured material. Until recently, it ilas been generally supposed that tilese cllanges were of a mere- ly mechanical nature. At all events, fexv persons ilave referred these results to causes of a strictly ellemical cilaracter. Investigations now point to very different conclusions. Since tIle experiments of WAnr~ und RODMAN, it has been obvious to cilemists that tile l)ursting of cannon is most frequently due to the corrosion, both superficially and in its inmost substance, even to the extent of a coniplete iloneycombing, especially in tile neigllborllood of tile vent of tile metal, by tile injec- tioll into its pores of the vapors of sulphur and sul- phide of potassium. Cllemist.s Ilave long knoxvn that pure distilled xvater will dissolve ferreous ilydrate, and in tile presence of free oxygen xviii q& ickly take up metallic iron into this form of sobltion. Hence, in a steam boiler, such por- tions of the internal surfaces as are subj ect to tile con- densation upon tilem of distilled water from tile steam, in an atmosphere xvhich alxvays contains free oxygen that had been dissolved in the water, and frequently under heat and pressure, must be botil corroded superficially and disi1lte~rated internally. In tills we have the cause of many of our most fearful dis- asters. How many lives ilave been lost by tile breaking of axles, springs, rails, etc., xvhicll might have been saved, ilad we known 110w to protect these completely from tile corroding action of tile oxygen of tile air, introduced in aqueous solution into tlleir pores and flaws, none can tell. The nexv experiment of steel rails, ill a clinlate hike ours, whose intense cold is known to de- stroy all tile viscosity of steel and heave oPly its brittle- ness, is contenlplated witil foreboding. Tills latter ease leads to tile suggestion that no question requires tile atteiltioll of tile inxestigator more tilan tilose con- ilected xvithl tile different kinds of consistence of mat- ter, tile influence of. various agents in modifying tile sanle, and tile ulodes of producing and conserving any desired fornl of consistence. GRAHAM ilas generalized all consistence under two ileads : tile crystalloid and colloid. It teems clear to us tilat to tilese must be added tile viscous or viscoid con~istence, if not still otiler distinct species. The effects of natural and otiler chemical agents upon the various forms of vulcanized rubber and conlpounds thereof now in use are undergoing investi- gation by one of tile most eminent of our American cilelnists, xvitll results of tile ilighest novelty and im- portance, in due time to be laid before tile public. must likewise be gradual and cumulative. All I Another great field for tile chemical engineerto ilimlall experiellee proves, ilevertileless, tilat tile law which much attentioll ilas been already given, but ilas by 110 means begun to yield its full fruitis in tile ~reservatioil froul decay, from fire, and otiler oestructive no-encies, of suell substances as stone, wood, and otiler nlateriala used in building and in tile construction of veilicles. It is clear that iron, as a ulaterial for tilese purpdses, is continually disappointing tile sailguille expectations of tilose wile do not understand xvell its inllerent defects ; and xve believe tile time will 50011 come Ivilen wood, so prepared chemically as to be in- combustible, indestructible, and a perfect non-conduc- tor of ileat, xviii be tile alillost universal material used 111 tile construction of buildillgs and vellicles, ex- cept of course tile nlachinery of the hatter. We will only allude, ill closilIg tills article, to tile re- markable application, of whiell we Ilave lately ileard, of a laboratory instrunlent, an electro-nlagnet, to the de- tection of fiaxvs and imperfections in the interior of a n~ass of iron or steel. The New Art of Fresco-Painting. Ti-ix art of stereocilromy must be considered as in- volving an entirely new mode of creating durable pictures upon walls, inasalucil as a new binding mate- rial is applied, whicil differs from any employed in tile usual nlodes of mural painting. By tilis binding nlate- rial, xvhlicil IS tile soluble glass of cofllmerce, tile colors become, as it xvere, silicifled; and pictures executed in this way distinguish themselves by a certain fresilness and a power of resisting atalospheric influences Ivilicil ordinary frescoes do not possess. In giving an account of this interesting mode of paintillg, xve silail confine ourselves to a general out- line of the method bywhicil KAULBACH, tile celebrated artist of Municil, and ECHTEII, ilave executed, in the nexv museun~ at Berlin, four large pictures, whicil are generally acknoxvledged to exilibit a great advance in tile art of nIural painting. Tile wall to be painted is first coated Witil a layer of ordinary hinle-nlortar, in order to equalize its unevenness. The sand employed, wilicil may be either silicious or calcareous, must l)e of even grain and xvell washed beforehand. Lime nlust be sparingly employed, so as to render the cement ratiler poor tilall otilerxvise. In tills and ill all the subsequemlt operations, pure rain-water lIllist be used. Tile plaster, tilus prepared, must be well dried and exposed to tile air for several days, so as to become en- tirely carbonated. Caustic 1mb would decompose tile soluble glass. Fucirs, tile inventor of stereoeilromy, reconlillends tile uloistening of the xvall several times Ivitil a solution of carbonate of amnlonia, so as to acce- lerate tile saturatioll of tlle lime. Wilen dry, it is xvaslled over several tinles xvitil a llloderatehy diluted solution of the so-called double xvater-glass, allow. ilIg it to dry each thlle. Tile ground being tilils prepared, the upper layer may be seen after added. It consists, like tile loxver one, of a lime-mortar, and is spread in the tilickness of about 0110 tentll of an mdl. Tile sand eIllployed ulust be Ivell Ivasiled, and of a graill not exceeding a certain size. Very fine powder must be rejected; and for tills reason it is best to pass it tiliougil a sieve. A ror~ll grain is ratiler advantageous; KAULBACH says it ougilt to feel like a rasp. For a picture to be viewed at a great distance, a coarser grain is required than for one designed for closer inspection. When tile coating is perfectly dry, i~ is sometimes rubbed witil a sllarp sandstone, In order to remove tIle layer formed of carbonate of hale. It is better, 110w- ever, to accomphisil tills by means of diluted phospiloric acid. Tile pilospilate of 1mb thus foraled b;nds tile soluble glass, a solutioll of wilicil, Ivhlell tile coat. .s d:y, is spread over tile surface. The same is dii :~ed w~.il its equal bulk of water, and tile operation is twtee re- peated. Too much xvater-glass prevents the ground froma taking tile colors. Tile ground being thus pre- pared, the painting n~ay be at once proceeded with; sonle delay, ilolvever, increases tile capacity for ab- sorption. The colors to be used must be ground with pure water, (we xviii speak of tileir preparation in a 10 The Manufacturer and Builder, subsequent article,) and the wall has also to be fre- quently sprinkled with water, in order to displace the air frnm the pores, and to insure titus the adherence of the colors. Nothing further remains to be done than to fix the colors properly with a solution of the soluble glass referred to, which operatien is accomplished by sprinkling the painting in the form of a fine shower or mist, then letting it dry, and repeatin~ the operation until the colors adhere so firmly that they can not be any more rubbed off by the finger. Old Says on Building. IN the reign of Charles the First, England was rich in eccentric characters, not the least of whom was old FULLER, the author of that curious work, The Holy and Profane State. Among various subjects he titus descants on building: lie that alters an old house is tied as a translatour to the original, and is confind to the pliancy of the first builder. Such a man were unwise to pluck down good old building to erect (perchance) worse new. But those that raise a new house from the ground are blame-worthy if they make it not hand- some, seeing to them method and confusion are both at a rate. In building we must respect Situation, Con- trivance, Receipt, Strength, and Beauty. Of SituationChiefly choose a wholesome aire. For aire is a dish one feeds on every minute, and therefore it need be good. Wherefore great men (xvho may build where they please, as poore men where titey can), if herein they prefer their profit above their health, I refer them to their physitians to make them pay for it accordingly. Next, a pleasant prospect i~ to be respected. A medly view best entertains the eyes,. refreshing the we ned beholder with exchange of obj ects. Yet I know a more profitable prospect, where the owner can only see his own land round about. A fair entrance with an easie ascent gives a great grace to a building. Where the hall is preferment out of the court, the parlour out of the hall (not as in some old buildings), where the doores are so low pygmies must stoop, and the rooms so high that giants may stand upright. But now we are come to ContrivanceLet not thy common rooms be severall, nor thy severall rooms be eomtnon. The hall ought to lie open, and so ou~ht passages and stairs (provided that the whole house be not spent in paths). Chambers and closets are to be private and retired. Light (Gods eldest daughter) is a principal beauty in a building: yet it shines not alike from all parts of heaven. An east-window welcomes the infant beams of the sun, before they are of strength to do any harm, and is offensive to none but a sluggard. A south-win- dow in summer is a chimney with a fire in ,t, and needs the screen of a curtain. In a west-windoxv in summer time, towards night, the sun grows low and over familiar, with more light than delight. A north- window is best for butteries and cellars, where the beere will be sowr for the suns smiling on it. Thorow- lights are best for rooms of entertainment, and win- dows on one side for dormitories. As for ReceiptA house had better be too little for a day, than too great for a year. And its easier bor- rowing of thy neighbour a brace of chambers for a night, titan a bag of money for a twelve month. It is in vain, therefore, to proportion the receipt to an ex- traordinary occasion, as those who by over-building titeir houses have dilapidated their lands, and their states have been pressed to death under the weight of their house. As for StrengthUountrey houses must be substan- tives, able to stand of themselves. Not, like city build- ings, supported by tifeir neighbours on either side. By strength we mean such as may resist weather and time, not invasion, castles being out of date in this peaceable age. As for the making of motes round about, it is questionable whether the fogs be not more unhealthful than the fish brings profit, or the water defence Beauty remains behind, as the last to be re garded, becauses houses are made to be lived in, not lookt on. Let not thy front look a squint on a stranger, but accost hint right at his entrance. Uniformity also much pleaseth the eye; and tis observed that freestone, like a fair complexion, soonest waxeth old, whilst brick keeps her beauty longest. Let thy office-houses observe the due distance front the mansion-house. Titose are too familiar which pre- sume to be of the same pile with it. Tite same may be said of stables and barns; without which a house is like a city without works, it can never hold out long. Gardens also are to attend in their place. When God (Genesis ii. 9) planted a garden eastward, lie made to grow out of the ground every tree pleasant to the sight, and good for food. Sure lie knew better what was proper to a garden, tItan those nowadayes therein only feed the eyes, and starve both taste and smell. To conclude, in building rather believe any man than an artificer in his own art for matter of charges, not that they cannot, but will not be faithful. Should they tell thee all the cost at the first, it would blast a young builder in the budding, and therefore they soothe thee up till it hiath cost thiee something to com- pute them. The spirit of building first possessed people after the fond, which then caused the confu- sion of languages, and since of the estate of many a man. The Progress of Building. As our nation grows, new cities spring up, and the older ones enlarge their proportions. As wealth ac- cumulates, the desire for display calls for the em~ergies of the builders, and a love of rivalry produces art ef- forts, which, in their turn, generate national taste. Building is thus the great monumental witness of our countrys progress in extent, in wealth, and iii art. It is in itself a great progressive science, and thiere is but one ihuit to its growthignorance. But as po- pular education draws out thie intellectual powers of our people, this can be no barrier to its progress among us, and the advance that is made in building will lead on to greater efforts still, which will of ne- cessity create a national character for our architecture that must be dependent for its success or failure on the earnest cultivation of science and the blending of art with nature. There is no want of man, save food, more imperative tItan that of protection from the vicissitudes of the weather. It was his first care, when driven forth to labor, to construct a shielter where nature had not furnished him with a cave; and to this day that want is uppermost in his desires, whether prompted by simple necessity or urged on by ardent ambition. Notwith- standing the spirit of equality which is supposed to govern republican institutions, there is a feeling of rivalry among us which keeps down this spirit. Our citizen who grows in wealth, likewise grows intoler- ant of equality. He must make his position visible, and raise his head above his neighbors. However de- precated this ambitious spirit may be by the meek teachers of religion, it yet leads to a noble end, in building up time greatness of our nation and cultivat- ing those refining arts that ennoble time mind and lead it up from nature to natures God. Our citiesnorth, south, east, and westare display- ing their wealth in time astonishing progress of build- ing. Our people seem to build, not for a generation, but for a season; and tIme structure which was admired for its -composition ten years ago is relentlessly torn down to-day to make room for a better. Titus our streets continually assume new features, and lie that would revisit time city he knew some years back will seek in vain for time landmarks lie once thought per- manent. In this respect New-York is but a main- 11 How necessary, then, is a thorough cultivation of the arts and sciences which belong to this comprehensive sphere, and how great should be the desire to forward and improve every effort to obtain perfection in their many branches! It is as a determined laborer in this good work that we enter the field, hoping by unceas- ing effort to promote its best interests, and give to all connected with its branches that information it is their interest to seek and to acquire. The progress of building is, as we have said, found- ed on scientific knowledge, and the required informa- tion is not to be expected of the architect only, but of time builder, and every artisan working with him. How general, then, is time demand for aids to learning in this field, and how necessary that all should avail themselves of these aids when opportunity offers! Time whole subject, in fact, turns on the one pivot self-interest. lIe, therefore, whto will not improve his opportunity, forgets or neglects his own interest, and must fall back to make room for others whose motto is Excelsior ! Chrorne~Yellow Paint. Tun compounds of the metal chromium are amno~~ time most useful and most common of all time substances used in time manufacture of paints. The colors mado from it range from green, through all shades of yellow and orange, to red, and are all, with hardly an excep- tion, bright and beautiful. For thiat reason they have superseded many paints formerly usedsuch, for in- stance, as orpiment, massicot, and otimers. Chromium was only discovered at time end of time last century, and time name given to itderived from time Greekwas chosen on account of time many colors that can be produced front it. It was a mere curiosity at first, until, in Maryland, extensive deposits were found him commibination with iron ore. This conmpound is analogous to magnetic iron ore, which consists of sesquloxide of iron and oxide of iron. In time same manner time chrome ore found consists of a conibination of sesquloxide of chromium and oxide of iron. This substance is that front which all preparations of euro- mium are derived. It is converted into a chironmate of potassa in time following nianner: Time ore, having been reduced to pomvder, is caicined with nitre, or with carbonate of potassa, quicklime being sometimes added, and imeated for a long tinme in a reverberatory furnace. The product is treated with water, and a yellow solution obtained, wimicim upon evaporation deposits henmon-yehlow crystals of citro- mate of potassa. These crystals are a combination of potassa within an acid formed by time chromiumo, and called chmromic acid. This acid is simnihar to sulphuric acid, and it forums, with time potassa, time above-named chmromate of potassa. Wimemi a small qtmantity of sul- pimuric acid is added to this salt, half time potussa is re- nioved, conmbining ivithm this acid, and time remaining half of the potassa conmbines with double time quantity of chiromuic acid, and thitins is time so-called neutral euro- rate of potassa converted into a bichronmate of po- tassa. Of timis salt immense quantities are nmanufac- tured for use in time arts. It forams beautiful red crys- tals. Dissolved in water, it forms, according to tIme amount dissolved, yellow, orange, or red solutions. One part will saturate ten parts of water. Time so- lution has acid properties, and is quite poisonous. In order, nomv, to nmake cimrome-yehlomv, all that is ne- cessary to be done is to nmake a solution of sonie lead salt, as, for instance, the acetate of lead, or, in other words, the sugar of lead, or time nitrate of lead. When such a solution is umixed with a solution of the chiro- mate or bichiromate of potassa, a yellow or orange pre- cipitate of chtromate of head will be formed, of which the simade may be regulated by observing certain par- ticulars wimich ivill be hereafter explained. Time preci- pitate, dried and boxed up for the trade, is manufac- tured in timis country upon a very large scale, and is known in Europe as American chrome-yellow. Unlike moth witness of time rule so general in all other cities many other articles, it may also be manufactured to throughout the length and breadth of the land. advantage on quite a small scale.

The Manufacturer and Builder, subsequent article,) and the wall has also to be fre- quently sprinkled with water, in order to displace the air frnm the pores, and to insure titus the adherence of the colors. Nothing further remains to be done than to fix the colors properly with a solution of the soluble glass referred to, which operatien is accomplished by sprinkling the painting in the form of a fine shower or mist, then letting it dry, and repeatin~ the operation until the colors adhere so firmly that they can not be any more rubbed off by the finger. Old Says on Building. IN the reign of Charles the First, England was rich in eccentric characters, not the least of whom was old FULLER, the author of that curious work, The Holy and Profane State. Among various subjects he titus descants on building: lie that alters an old house is tied as a translatour to the original, and is confind to the pliancy of the first builder. Such a man were unwise to pluck down good old building to erect (perchance) worse new. But those that raise a new house from the ground are blame-worthy if they make it not hand- some, seeing to them method and confusion are both at a rate. In building we must respect Situation, Con- trivance, Receipt, Strength, and Beauty. Of SituationChiefly choose a wholesome aire. For aire is a dish one feeds on every minute, and therefore it need be good. Wherefore great men (xvho may build where they please, as poore men where titey can), if herein they prefer their profit above their health, I refer them to their physitians to make them pay for it accordingly. Next, a pleasant prospect i~ to be respected. A medly view best entertains the eyes,. refreshing the we ned beholder with exchange of obj ects. Yet I know a more profitable prospect, where the owner can only see his own land round about. A fair entrance with an easie ascent gives a great grace to a building. Where the hall is preferment out of the court, the parlour out of the hall (not as in some old buildings), where the doores are so low pygmies must stoop, and the rooms so high that giants may stand upright. But now we are come to ContrivanceLet not thy common rooms be severall, nor thy severall rooms be eomtnon. The hall ought to lie open, and so ou~ht passages and stairs (provided that the whole house be not spent in paths). Chambers and closets are to be private and retired. Light (Gods eldest daughter) is a principal beauty in a building: yet it shines not alike from all parts of heaven. An east-window welcomes the infant beams of the sun, before they are of strength to do any harm, and is offensive to none but a sluggard. A south-win- dow in summer is a chimney with a fire in ,t, and needs the screen of a curtain. In a west-windoxv in summer time, towards night, the sun grows low and over familiar, with more light than delight. A north- window is best for butteries and cellars, where the beere will be sowr for the suns smiling on it. Thorow- lights are best for rooms of entertainment, and win- dows on one side for dormitories. As for ReceiptA house had better be too little for a day, than too great for a year. And its easier bor- rowing of thy neighbour a brace of chambers for a night, titan a bag of money for a twelve month. It is in vain, therefore, to proportion the receipt to an ex- traordinary occasion, as those who by over-building titeir houses have dilapidated their lands, and their states have been pressed to death under the weight of their house. As for StrengthUountrey houses must be substan- tives, able to stand of themselves. Not, like city build- ings, supported by tifeir neighbours on either side. By strength we mean such as may resist weather and time, not invasion, castles being out of date in this peaceable age. As for the making of motes round about, it is questionable whether the fogs be not more unhealthful than the fish brings profit, or the water defence Beauty remains behind, as the last to be re garded, becauses houses are made to be lived in, not lookt on. Let not thy front look a squint on a stranger, but accost hint right at his entrance. Uniformity also much pleaseth the eye; and tis observed that freestone, like a fair complexion, soonest waxeth old, whilst brick keeps her beauty longest. Let thy office-houses observe the due distance front the mansion-house. Titose are too familiar which pre- sume to be of the same pile with it. Tite same may be said of stables and barns; without which a house is like a city without works, it can never hold out long. Gardens also are to attend in their place. When God (Genesis ii. 9) planted a garden eastward, lie made to grow out of the ground every tree pleasant to the sight, and good for food. Sure lie knew better what was proper to a garden, tItan those nowadayes therein only feed the eyes, and starve both taste and smell. To conclude, in building rather believe any man than an artificer in his own art for matter of charges, not that they cannot, but will not be faithful. Should they tell thee all the cost at the first, it would blast a young builder in the budding, and therefore they soothe thee up till it hiath cost thiee something to com- pute them. The spirit of building first possessed people after the fond, which then caused the confu- sion of languages, and since of the estate of many a man. The Progress of Building. As our nation grows, new cities spring up, and the older ones enlarge their proportions. As wealth ac- cumulates, the desire for display calls for the em~ergies of the builders, and a love of rivalry produces art ef- forts, which, in their turn, generate national taste. Building is thus the great monumental witness of our countrys progress in extent, in wealth, and iii art. It is in itself a great progressive science, and thiere is but one ihuit to its growthignorance. But as po- pular education draws out thie intellectual powers of our people, this can be no barrier to its progress among us, and the advance that is made in building will lead on to greater efforts still, which will of ne- cessity create a national character for our architecture that must be dependent for its success or failure on the earnest cultivation of science and the blending of art with nature. There is no want of man, save food, more imperative tItan that of protection from the vicissitudes of the weather. It was his first care, when driven forth to labor, to construct a shielter where nature had not furnished him with a cave; and to this day that want is uppermost in his desires, whether prompted by simple necessity or urged on by ardent ambition. Notwith- standing the spirit of equality which is supposed to govern republican institutions, there is a feeling of rivalry among us which keeps down this spirit. Our citizen who grows in wealth, likewise grows intoler- ant of equality. He must make his position visible, and raise his head above his neighbors. However de- precated this ambitious spirit may be by the meek teachers of religion, it yet leads to a noble end, in building up time greatness of our nation and cultivat- ing those refining arts that ennoble time mind and lead it up from nature to natures God. Our citiesnorth, south, east, and westare display- ing their wealth in time astonishing progress of build- ing. Our people seem to build, not for a generation, but for a season; and tIme structure which was admired for its -composition ten years ago is relentlessly torn down to-day to make room for a better. Titus our streets continually assume new features, and lie that would revisit time city he knew some years back will seek in vain for time landmarks lie once thought per- manent. In this respect New-York is but a main- 11 How necessary, then, is a thorough cultivation of the arts and sciences which belong to this comprehensive sphere, and how great should be the desire to forward and improve every effort to obtain perfection in their many branches! It is as a determined laborer in this good work that we enter the field, hoping by unceas- ing effort to promote its best interests, and give to all connected with its branches that information it is their interest to seek and to acquire. The progress of building is, as we have said, found- ed on scientific knowledge, and the required informa- tion is not to be expected of the architect only, but of time builder, and every artisan working with him. How general, then, is time demand for aids to learning in this field, and how necessary that all should avail themselves of these aids when opportunity offers! Time whole subject, in fact, turns on the one pivot self-interest. lIe, therefore, whto will not improve his opportunity, forgets or neglects his own interest, and must fall back to make room for others whose motto is Excelsior ! Chrorne~Yellow Paint. Tun compounds of the metal chromium are amno~~ time most useful and most common of all time substances used in time manufacture of paints. The colors mado from it range from green, through all shades of yellow and orange, to red, and are all, with hardly an excep- tion, bright and beautiful. For thiat reason they have superseded many paints formerly usedsuch, for in- stance, as orpiment, massicot, and otimers. Chromium was only discovered at time end of time last century, and time name given to itderived from time Greekwas chosen on account of time many colors that can be produced front it. It was a mere curiosity at first, until, in Maryland, extensive deposits were found him commibination with iron ore. This conmpound is analogous to magnetic iron ore, which consists of sesquloxide of iron and oxide of iron. In time same manner time chrome ore found consists of a conibination of sesquloxide of chromium and oxide of iron. This substance is that front which all preparations of euro- mium are derived. It is converted into a chironmate of potassa in time following nianner: Time ore, having been reduced to pomvder, is caicined with nitre, or with carbonate of potassa, quicklime being sometimes added, and imeated for a long tinme in a reverberatory furnace. The product is treated with water, and a yellow solution obtained, wimicim upon evaporation deposits henmon-yehlow crystals of citro- mate of potassa. These crystals are a combination of potassa within an acid formed by time chromiumo, and called chmromic acid. This acid is simnihar to sulphuric acid, and it forums, with time potassa, time above-named chmromate of potassa. Wimemi a small qtmantity of sul- pimuric acid is added to this salt, half time potussa is re- nioved, conmbining ivithm this acid, and time remaining half of the potassa conmbines with double time quantity of chiromuic acid, and thitins is time so-called neutral euro- rate of potassa converted into a bichronmate of po- tassa. Of timis salt immense quantities are nmanufac- tured for use in time arts. It forams beautiful red crys- tals. Dissolved in water, it forms, according to tIme amount dissolved, yellow, orange, or red solutions. One part will saturate ten parts of water. Time so- lution has acid properties, and is quite poisonous. In order, nomv, to nmake cimrome-yehlomv, all that is ne- cessary to be done is to nmake a solution of sonie lead salt, as, for instance, the acetate of lead, or, in other words, the sugar of lead, or time nitrate of lead. When such a solution is umixed with a solution of the chiro- mate or bichiromate of potassa, a yellow or orange pre- cipitate of chtromate of head will be formed, of which the simade may be regulated by observing certain par- ticulars wimich ivill be hereafter explained. Time preci- pitate, dried and boxed up for the trade, is manufac- tured in timis country upon a very large scale, and is known in Europe as American chrome-yellow. Unlike moth witness of time rule so general in all other cities many other articles, it may also be manufactured to throughout the length and breadth of the land. advantage on quite a small scale.

The Manufacturer and Builder, subsequent article,) and the wall has also to be fre- quently sprinkled with water, in order to displace the air frnm the pores, and to insure titus the adherence of the colors. Nothing further remains to be done than to fix the colors properly with a solution of the soluble glass referred to, which operatien is accomplished by sprinkling the painting in the form of a fine shower or mist, then letting it dry, and repeatin~ the operation until the colors adhere so firmly that they can not be any more rubbed off by the finger. Old Says on Building. IN the reign of Charles the First, England was rich in eccentric characters, not the least of whom was old FULLER, the author of that curious work, The Holy and Profane State. Among various subjects he titus descants on building: lie that alters an old house is tied as a translatour to the original, and is confind to the pliancy of the first builder. Such a man were unwise to pluck down good old building to erect (perchance) worse new. But those that raise a new house from the ground are blame-worthy if they make it not hand- some, seeing to them method and confusion are both at a rate. In building we must respect Situation, Con- trivance, Receipt, Strength, and Beauty. Of SituationChiefly choose a wholesome aire. For aire is a dish one feeds on every minute, and therefore it need be good. Wherefore great men (xvho may build where they please, as poore men where titey can), if herein they prefer their profit above their health, I refer them to their physitians to make them pay for it accordingly. Next, a pleasant prospect i~ to be respected. A medly view best entertains the eyes,. refreshing the we ned beholder with exchange of obj ects. Yet I know a more profitable prospect, where the owner can only see his own land round about. A fair entrance with an easie ascent gives a great grace to a building. Where the hall is preferment out of the court, the parlour out of the hall (not as in some old buildings), where the doores are so low pygmies must stoop, and the rooms so high that giants may stand upright. But now we are come to ContrivanceLet not thy common rooms be severall, nor thy severall rooms be eomtnon. The hall ought to lie open, and so ou~ht passages and stairs (provided that the whole house be not spent in paths). Chambers and closets are to be private and retired. Light (Gods eldest daughter) is a principal beauty in a building: yet it shines not alike from all parts of heaven. An east-window welcomes the infant beams of the sun, before they are of strength to do any harm, and is offensive to none but a sluggard. A south-win- dow in summer is a chimney with a fire in ,t, and needs the screen of a curtain. In a west-windoxv in summer time, towards night, the sun grows low and over familiar, with more light than delight. A north- window is best for butteries and cellars, where the beere will be sowr for the suns smiling on it. Thorow- lights are best for rooms of entertainment, and win- dows on one side for dormitories. As for ReceiptA house had better be too little for a day, than too great for a year. And its easier bor- rowing of thy neighbour a brace of chambers for a night, titan a bag of money for a twelve month. It is in vain, therefore, to proportion the receipt to an ex- traordinary occasion, as those who by over-building titeir houses have dilapidated their lands, and their states have been pressed to death under the weight of their house. As for StrengthUountrey houses must be substan- tives, able to stand of themselves. Not, like city build- ings, supported by tifeir neighbours on either side. By strength we mean such as may resist weather and time, not invasion, castles being out of date in this peaceable age. As for the making of motes round about, it is questionable whether the fogs be not more unhealthful than the fish brings profit, or the water defence Beauty remains behind, as the last to be re garded, becauses houses are made to be lived in, not lookt on. Let not thy front look a squint on a stranger, but accost hint right at his entrance. Uniformity also much pleaseth the eye; and tis observed that freestone, like a fair complexion, soonest waxeth old, whilst brick keeps her beauty longest. Let thy office-houses observe the due distance front the mansion-house. Titose are too familiar which pre- sume to be of the same pile with it. Tite same may be said of stables and barns; without which a house is like a city without works, it can never hold out long. Gardens also are to attend in their place. When God (Genesis ii. 9) planted a garden eastward, lie made to grow out of the ground every tree pleasant to the sight, and good for food. Sure lie knew better what was proper to a garden, tItan those nowadayes therein only feed the eyes, and starve both taste and smell. To conclude, in building rather believe any man than an artificer in his own art for matter of charges, not that they cannot, but will not be faithful. Should they tell thee all the cost at the first, it would blast a young builder in the budding, and therefore they soothe thee up till it hiath cost thiee something to com- pute them. The spirit of building first possessed people after the fond, which then caused the confu- sion of languages, and since of the estate of many a man. The Progress of Building. As our nation grows, new cities spring up, and the older ones enlarge their proportions. As wealth ac- cumulates, the desire for display calls for the em~ergies of the builders, and a love of rivalry produces art ef- forts, which, in their turn, generate national taste. Building is thus the great monumental witness of our countrys progress in extent, in wealth, and iii art. It is in itself a great progressive science, and thiere is but one ihuit to its growthignorance. But as po- pular education draws out thie intellectual powers of our people, this can be no barrier to its progress among us, and the advance that is made in building will lead on to greater efforts still, which will of ne- cessity create a national character for our architecture that must be dependent for its success or failure on the earnest cultivation of science and the blending of art with nature. There is no want of man, save food, more imperative tItan that of protection from the vicissitudes of the weather. It was his first care, when driven forth to labor, to construct a shielter where nature had not furnished him with a cave; and to this day that want is uppermost in his desires, whether prompted by simple necessity or urged on by ardent ambition. Notwith- standing the spirit of equality which is supposed to govern republican institutions, there is a feeling of rivalry among us which keeps down this spirit. Our citizen who grows in wealth, likewise grows intoler- ant of equality. He must make his position visible, and raise his head above his neighbors. However de- precated this ambitious spirit may be by the meek teachers of religion, it yet leads to a noble end, in building up time greatness of our nation and cultivat- ing those refining arts that ennoble time mind and lead it up from nature to natures God. Our citiesnorth, south, east, and westare display- ing their wealth in time astonishing progress of build- ing. Our people seem to build, not for a generation, but for a season; and tIme structure which was admired for its -composition ten years ago is relentlessly torn down to-day to make room for a better. Titus our streets continually assume new features, and lie that would revisit time city he knew some years back will seek in vain for time landmarks lie once thought per- manent. In this respect New-York is but a main- 11 How necessary, then, is a thorough cultivation of the arts and sciences which belong to this comprehensive sphere, and how great should be the desire to forward and improve every effort to obtain perfection in their many branches! It is as a determined laborer in this good work that we enter the field, hoping by unceas- ing effort to promote its best interests, and give to all connected with its branches that information it is their interest to seek and to acquire. The progress of building is, as we have said, found- ed on scientific knowledge, and the required informa- tion is not to be expected of the architect only, but of time builder, and every artisan working with him. How general, then, is time demand for aids to learning in this field, and how necessary that all should avail themselves of these aids when opportunity offers! Time whole subject, in fact, turns on the one pivot self-interest. lIe, therefore, whto will not improve his opportunity, forgets or neglects his own interest, and must fall back to make room for others whose motto is Excelsior ! Chrorne~Yellow Paint. Tun compounds of the metal chromium are amno~~ time most useful and most common of all time substances used in time manufacture of paints. The colors mado from it range from green, through all shades of yellow and orange, to red, and are all, with hardly an excep- tion, bright and beautiful. For thiat reason they have superseded many paints formerly usedsuch, for in- stance, as orpiment, massicot, and otimers. Chromium was only discovered at time end of time last century, and time name given to itderived from time Greekwas chosen on account of time many colors that can be produced front it. It was a mere curiosity at first, until, in Maryland, extensive deposits were found him commibination with iron ore. This conmpound is analogous to magnetic iron ore, which consists of sesquloxide of iron and oxide of iron. In time same manner time chrome ore found consists of a conibination of sesquloxide of chromium and oxide of iron. This substance is that front which all preparations of euro- mium are derived. It is converted into a chironmate of potassa in time following nianner: Time ore, having been reduced to pomvder, is caicined with nitre, or with carbonate of potassa, quicklime being sometimes added, and imeated for a long tinme in a reverberatory furnace. The product is treated with water, and a yellow solution obtained, wimicim upon evaporation deposits henmon-yehlow crystals of citro- mate of potassa. These crystals are a combination of potassa within an acid formed by time chromiumo, and called chmromic acid. This acid is simnihar to sulphuric acid, and it forums, with time potassa, time above-named chmromate of potassa. Wimemi a small qtmantity of sul- pimuric acid is added to this salt, half time potussa is re- nioved, conmbining ivithm this acid, and time remaining half of the potassa conmbines with double time quantity of chiromuic acid, and thitins is time so-called neutral euro- rate of potassa converted into a bichronmate of po- tassa. Of timis salt immense quantities are nmanufac- tured for use in time arts. It forams beautiful red crys- tals. Dissolved in water, it forms, according to tIme amount dissolved, yellow, orange, or red solutions. One part will saturate ten parts of water. Time so- lution has acid properties, and is quite poisonous. In order, nomv, to nmake cimrome-yehlomv, all that is ne- cessary to be done is to nmake a solution of sonie lead salt, as, for instance, the acetate of lead, or, in other words, the sugar of lead, or time nitrate of lead. When such a solution is umixed with a solution of the chiro- mate or bichiromate of potassa, a yellow or orange pre- cipitate of chtromate of head will be formed, of which the simade may be regulated by observing certain par- ticulars wimich ivill be hereafter explained. Time preci- pitate, dried and boxed up for the trade, is manufac- tured in timis country upon a very large scale, and is known in Europe as American chrome-yellow. Unlike moth witness of time rule so general in all other cities many other articles, it may also be manufactured to throughout the length and breadth of the land. advantage on quite a small scale.

The Manufacturer and Builder, subsequent article,) and the wall has also to be fre- quently sprinkled with water, in order to displace the air frnm the pores, and to insure titus the adherence of the colors. Nothing further remains to be done than to fix the colors properly with a solution of the soluble glass referred to, which operatien is accomplished by sprinkling the painting in the form of a fine shower or mist, then letting it dry, and repeatin~ the operation until the colors adhere so firmly that they can not be any more rubbed off by the finger. Old Says on Building. IN the reign of Charles the First, England was rich in eccentric characters, not the least of whom was old FULLER, the author of that curious work, The Holy and Profane State. Among various subjects he titus descants on building: lie that alters an old house is tied as a translatour to the original, and is confind to the pliancy of the first builder. Such a man were unwise to pluck down good old building to erect (perchance) worse new. But those that raise a new house from the ground are blame-worthy if they make it not hand- some, seeing to them method and confusion are both at a rate. In building we must respect Situation, Con- trivance, Receipt, Strength, and Beauty. Of SituationChiefly choose a wholesome aire. For aire is a dish one feeds on every minute, and therefore it need be good. Wherefore great men (xvho may build where they please, as poore men where titey can), if herein they prefer their profit above their health, I refer them to their physitians to make them pay for it accordingly. Next, a pleasant prospect i~ to be respected. A medly view best entertains the eyes,. refreshing the we ned beholder with exchange of obj ects. Yet I know a more profitable prospect, where the owner can only see his own land round about. A fair entrance with an easie ascent gives a great grace to a building. Where the hall is preferment out of the court, the parlour out of the hall (not as in some old buildings), where the doores are so low pygmies must stoop, and the rooms so high that giants may stand upright. But now we are come to ContrivanceLet not thy common rooms be severall, nor thy severall rooms be eomtnon. The hall ought to lie open, and so ou~ht passages and stairs (provided that the whole house be not spent in paths). Chambers and closets are to be private and retired. Light (Gods eldest daughter) is a principal beauty in a building: yet it shines not alike from all parts of heaven. An east-window welcomes the infant beams of the sun, before they are of strength to do any harm, and is offensive to none but a sluggard. A south-win- dow in summer is a chimney with a fire in ,t, and needs the screen of a curtain. In a west-windoxv in summer time, towards night, the sun grows low and over familiar, with more light than delight. A north- window is best for butteries and cellars, where the beere will be sowr for the suns smiling on it. Thorow- lights are best for rooms of entertainment, and win- dows on one side for dormitories. As for ReceiptA house had better be too little for a day, than too great for a year. And its easier bor- rowing of thy neighbour a brace of chambers for a night, titan a bag of money for a twelve month. It is in vain, therefore, to proportion the receipt to an ex- traordinary occasion, as those who by over-building titeir houses have dilapidated their lands, and their states have been pressed to death under the weight of their house. As for StrengthUountrey houses must be substan- tives, able to stand of themselves. Not, like city build- ings, supported by tifeir neighbours on either side. By strength we mean such as may resist weather and time, not invasion, castles being out of date in this peaceable age. As for the making of motes round about, it is questionable whether the fogs be not more unhealthful than the fish brings profit, or the water defence Beauty remains behind, as the last to be re garded, becauses houses are made to be lived in, not lookt on. Let not thy front look a squint on a stranger, but accost hint right at his entrance. Uniformity also much pleaseth the eye; and tis observed that freestone, like a fair complexion, soonest waxeth old, whilst brick keeps her beauty longest. Let thy office-houses observe the due distance front the mansion-house. Titose are too familiar which pre- sume to be of the same pile with it. Tite same may be said of stables and barns; without which a house is like a city without works, it can never hold out long. Gardens also are to attend in their place. When God (Genesis ii. 9) planted a garden eastward, lie made to grow out of the ground every tree pleasant to the sight, and good for food. Sure lie knew better what was proper to a garden, tItan those nowadayes therein only feed the eyes, and starve both taste and smell. To conclude, in building rather believe any man than an artificer in his own art for matter of charges, not that they cannot, but will not be faithful. Should they tell thee all the cost at the first, it would blast a young builder in the budding, and therefore they soothe thee up till it hiath cost thiee something to com- pute them. The spirit of building first possessed people after the fond, which then caused the confu- sion of languages, and since of the estate of many a man. The Progress of Building. As our nation grows, new cities spring up, and the older ones enlarge their proportions. As wealth ac- cumulates, the desire for display calls for the em~ergies of the builders, and a love of rivalry produces art ef- forts, which, in their turn, generate national taste. Building is thus the great monumental witness of our countrys progress in extent, in wealth, and iii art. It is in itself a great progressive science, and thiere is but one ihuit to its growthignorance. But as po- pular education draws out thie intellectual powers of our people, this can be no barrier to its progress among us, and the advance that is made in building will lead on to greater efforts still, which will of ne- cessity create a national character for our architecture that must be dependent for its success or failure on the earnest cultivation of science and the blending of art with nature. There is no want of man, save food, more imperative tItan that of protection from the vicissitudes of the weather. It was his first care, when driven forth to labor, to construct a shielter where nature had not furnished him with a cave; and to this day that want is uppermost in his desires, whether prompted by simple necessity or urged on by ardent ambition. Notwith- standing the spirit of equality which is supposed to govern republican institutions, there is a feeling of rivalry among us which keeps down this spirit. Our citizen who grows in wealth, likewise grows intoler- ant of equality. He must make his position visible, and raise his head above his neighbors. However de- precated this ambitious spirit may be by the meek teachers of religion, it yet leads to a noble end, in building up time greatness of our nation and cultivat- ing those refining arts that ennoble time mind and lead it up from nature to natures God. Our citiesnorth, south, east, and westare display- ing their wealth in time astonishing progress of build- ing. Our people seem to build, not for a generation, but for a season; and tIme structure which was admired for its -composition ten years ago is relentlessly torn down to-day to make room for a better. Titus our streets continually assume new features, and lie that would revisit time city he knew some years back will seek in vain for time landmarks lie once thought per- manent. In this respect New-York is but a main- 11 How necessary, then, is a thorough cultivation of the arts and sciences which belong to this comprehensive sphere, and how great should be the desire to forward and improve every effort to obtain perfection in their many branches! It is as a determined laborer in this good work that we enter the field, hoping by unceas- ing effort to promote its best interests, and give to all connected with its branches that information it is their interest to seek and to acquire. The progress of building is, as we have said, found- ed on scientific knowledge, and the required informa- tion is not to be expected of the architect only, but of time builder, and every artisan working with him. How general, then, is time demand for aids to learning in this field, and how necessary that all should avail themselves of these aids when opportunity offers! Time whole subject, in fact, turns on the one pivot self-interest. lIe, therefore, whto will not improve his opportunity, forgets or neglects his own interest, and must fall back to make room for others whose motto is Excelsior ! Chrorne~Yellow Paint. Tun compounds of the metal chromium are amno~~ time most useful and most common of all time substances used in time manufacture of paints. The colors mado from it range from green, through all shades of yellow and orange, to red, and are all, with hardly an excep- tion, bright and beautiful. For thiat reason they have superseded many paints formerly usedsuch, for in- stance, as orpiment, massicot, and otimers. Chromium was only discovered at time end of time last century, and time name given to itderived from time Greekwas chosen on account of time many colors that can be produced front it. It was a mere curiosity at first, until, in Maryland, extensive deposits were found him commibination with iron ore. This conmpound is analogous to magnetic iron ore, which consists of sesquloxide of iron and oxide of iron. In time same manner time chrome ore found consists of a conibination of sesquloxide of chromium and oxide of iron. This substance is that front which all preparations of euro- mium are derived. It is converted into a chironmate of potassa in time following nianner: Time ore, having been reduced to pomvder, is caicined with nitre, or with carbonate of potassa, quicklime being sometimes added, and imeated for a long tinme in a reverberatory furnace. The product is treated with water, and a yellow solution obtained, wimicim upon evaporation deposits henmon-yehlow crystals of citro- mate of potassa. These crystals are a combination of potassa within an acid formed by time chromiumo, and called chmromic acid. This acid is simnihar to sulphuric acid, and it forums, with time potassa, time above-named chmromate of potassa. Wimemi a small qtmantity of sul- pimuric acid is added to this salt, half time potussa is re- nioved, conmbining ivithm this acid, and time remaining half of the potassa conmbines with double time quantity of chiromuic acid, and thitins is time so-called neutral euro- rate of potassa converted into a bichronmate of po- tassa. Of timis salt immense quantities are nmanufac- tured for use in time arts. It forams beautiful red crys- tals. Dissolved in water, it forms, according to tIme amount dissolved, yellow, orange, or red solutions. One part will saturate ten parts of water. Time so- lution has acid properties, and is quite poisonous. In order, nomv, to nmake cimrome-yehlomv, all that is ne- cessary to be done is to nmake a solution of sonie lead salt, as, for instance, the acetate of lead, or, in other words, the sugar of lead, or time nitrate of lead. When such a solution is umixed with a solution of the chiro- mate or bichiromate of potassa, a yellow or orange pre- cipitate of chtromate of head will be formed, of which the simade may be regulated by observing certain par- ticulars wimich ivill be hereafter explained. Time preci- pitate, dried and boxed up for the trade, is manufac- tured in timis country upon a very large scale, and is known in Europe as American chrome-yellow. Unlike moth witness of time rule so general in all other cities many other articles, it may also be manufactured to throughout the length and breadth of the land. advantage on quite a small scale. The Manufacturer and Builder. Hints for Sign-Painters. As simple and ~~asy as it may seem to be able to let- ter a sign properly, it must be admitted that there are but few that are well lettered, and so made as to be attractive both in color and style of letter. The conviction is forced upon the observer that the majority of signs are overdone, donstrained, and evidently de- signed in very bad taste. In addition to all conceiva- ble forms and shapes of signsand among these forms we may enumerate long, round, square, oval, trian- gular, hexagonal, polygonal, scroll, stellated, prisma- tic, animal, and floral-shapedwe observe as many forms and styles of letter, each style being somewhat peculiar in itself, and in some degree original with the artist who desigr~ed it. We are not apt to notice small signs unless we are seeking particularly for them, or are interested in something connected therewith unusually large and largely lettered signs escape our observa- tion by being so excessively obvious. Scanty-lettered signs we do not often care to read the second time, as we get but little satisfaction by so doing, while pro- fusely lettered ones we do not read, for it is often too tedious. The signs that are generally remembered are those that are in size neither too large nor too small, neither gaudy nor tame in their coloring, neither scanty nor profuse in their lettering, and that give, in plain letters and in a few words, the information they have to convey. A sign of this character carries a correct business cast with it, and as we enter the establishment we feel quite sure that the proceedings and business within will harmonize with the 8igm with- out. A plain and direct business should be represented by a plain parallelogram form of sign, with a plain, bold lett~r that seems to tell you that things are done as they should be, and indicative that a balance-sheet is made out at the end of each financial year. When we see signs that are overlarge, or, on the other hand, too small, we are apt to imagine that the trade of the establishment to which they belong corresponds to their respective peculiarities. There seems to be a growing indication of press- ing the forms of masculine and female figures into service, and making them perform the duties of the signboard. The Goddess of Liberty, with outstretched arm resting on her star-studded shield, resplendent with stars and stripes of an indefinite number, points to the oyster-cellar, or the retreat where flows the lager; the American eagle, in brass and Dutch- leaf gold, is perched over the portals of the entrance where pinchbeck watches are sold. Male and female aborigines, coarsely painted with vermilion or be- daubed with burnt amber, stolid, ill-shaped, and nearly nude, together with the sooty African, the swarthy Turk, the kilted Highlander, and fun-loving Punch, dressed in gaudy, nondescript irobes, tell us where the scented maccaboy and other snuffs, or the choicest varieties of the weed, may be obtained. But good taste admits that the majority of these forms are but caricatures of true signs. They are not at all intended to represent the word business in a true, substantial, or commercial sense. It may not be out of place here to make a few re- marks relative to show-cards, since they are nothing but miniature signs. They embody as many charac- teristics as the permanent signboard, and are as much admired or condemned by the lovers of good taste. As the show-card, or even the business card, is an isolated piece of work, harmony of typographic group- ing ~nust be sought for. As in a sign, a crowding to- gether of the words produces confusion, and too much blank space causes a painful contrast between the color of the card and that of the ink. Moreover, an unequal gradation of the sizes of the letters, or the lines unduly spaced, is equally distasteful. As we hastily look at a business card, we expect to see at a glance the name of the firm it represents, as well as their business. Like a business sign, a business card should be printed in a plain, bold letter, the name of the business being the most conspicuous, as if it were not afraid of being inspected. The names of the firm should also be bold, yet not too prominent, as if modesty was one of their peculiar characteristics. Then the place where their business is conducted should be in a smaller letter, as if not pushing itself too much in your way, and the necessary details should thereafter follow in a plain letter, corresponding with the other general features of it. Like signs, the card that is the most admired is plain, of medium size, in conspicuous print, concisely worded, and with an even margin areund the edges, giving relief to the reading matter, which it incloses like a frame. Large-sized cards we do not so often notice or keep, unless we are particularly interested in them, especially if they are profusely lettered; we lay them aside until we feel that we have leisure to peruse them. Small cards we notice but little, as their dwarf proportions seem to carry an air of a limited business. It is more to the distorted and ill-proportioned ap- pearance of letters as seen upon signs and show-cards that we would call attention. A person who has a love for beautiful and correct letters can not be other- wise than pained at such distorted ones. Probably there is no art more difficult of attainment, and one in which so few persons are proficient, as that of making letters of the style called Roman; yet this letter is the one in which our books and papers are printed, and the one most commonly presented to the eye. However perfectly formed these letters may be when shaped by the art of the die-sinker, as seen in the impression produced by printing-types, never- theless, sign-boards that at every step meet our eyes attest that upon them are many unsuccessful attempts to form well-proportioned letters. Among a few of ~he faults that are evident we will iuention that the letters A, V. and W often encroach upon each others premises, and if a vertical line were drawn between two of them, more or less of each letter would be cut off. That each letter must be inclosed within a space determined by right angles, as is seen upon a printers type, seems not to have entered the mind of the artist. It is nothing uncommon to see a total disregard of the rules of proportion in reference to the space that letters should occupy. The Roman letter, as employed by sign-painters, is capable of being extended from its common width, and is also capable of being condensed, and is known by the terms of common, extended, and condensed letter, each having the same height, but different widths. These three proportions are amply sufficient for ordi- udry signs. The makers of type have extra-extended and also extra-condensed letters, but these forms are not often called into requisition by the sign or show- card painter. It will be observed that, when capital letters are placed in the order of their width, the letter I occupies the least space ; J is a little wider; C, L, 5, and Z occupy the third place; 0 and Q, the fourth; B, D, E, F, P, T, and & , the fifth; G, U, V, and Y, the sixth; A, K, R, and X, the seventh; H and N, the eighth; M, the ninth; and W, the tenth; ~ and ~ occupy a space between the ninth and tenth spaces. This division of the alphabet may be of . assistance to those who are sometimes at a loss what proportional width to give letters when grouped together. We see, then, if the letter I be taken as one width, A and the others of the seventh group occupy each twice the width of I; the third, or C group, one and a half. By spacing an alphabet with dividers, the cor- rect width that spaces of each division should occupy can be readily and correctly ascertained. Of the small letters, or, as they are termed by printers, the lower-case letters, we notice that i, j, and 1 are the least and the same in width; f and t then follow, being a little wider; the third space is filled by c, e, o, r, and s; the fourth space is occupied by a, b, d, g, p, q, and z; the fifth by h, k, n, ir, v, x, and y; the seventh by m and w. The space occupied by if, fi, fi, ~, and ce is the same as that of the capital letters B, D, and others of that series, which also . very nearly corre- sponds to the small letters h, k, etc. The space occu- pied by ffi and ifi is the same as that required for M. The dollar mark, $, has the same width as the letter J. In a comparison of the small letters with the capitals, we find that i, j, and 1 are less in width than the capital I, which very nearly corresponds fo the space occupied by f and t. The third space of the small letters falls between that of I and J, while the fourth is the same as that of the capital J. The small letters h, k, etc., of the fifth space are the same as the space of the capitals C, L, 5, and Z. The figures, or Arabic numerals, may be divided into four groups. The figure 1 is first, occupyin~ the least space. The figure 7 is next in width; then fol- low 2, 3, 4, 5, 6, 5, and 9, and lastly the 0, generally made a little wider. The figures 1, 7, and the letter I occupy the same width; with the exception of the 0, which occupies the same space as L, 5, and Z, the other figures are of the same width as the capital let- ter J. If one would form well-proportioned letters, he should divide the alphabet into groups in the order we have indicated. Since the capital I occupies the least. space, it may be taken as a .standard. The eye and judgment, assisted by this scale of widths, will enable any person to obtain a very good idea of the space the others should occupy. In addition to proportioning the width, it will be observed that icany letters, as A, M, N, V, W, X, Y~ and Z, are made up in part of oblique lines. It will: be further observed that the angles and lines of A. differ from those of K, and both A and K differ in: their angles from X and W. A closer examination of well-proportioned letters xviii show that the inclined~ portions of A, M, and V have the same angles, those of X,Y, and Z are similar, and K and W, the two remain- ing letters, are made in part with unlike oblique lines, and also differing from the others mentioned. There are, therefore, but four angles in all these letters, and if they could be determined, there would then be an easy rule governing their formation. Taste and circumstances determine the width of the common Roman, the extended, or condensed letter. As they . thus differ, the oblique lines of the letters so formed also differ. To approximate to the proper angles for each of the three kinds, let one provide himself with three pieces of thin board, metal, or even thick paper, made with one side and the bottom at right angles to each other; the other side is cut with four angles, as seen in the figures. Fig. 1 shows the angles for the condensed letter; Fig; 2, those for the common Roman letter; and Fig. 3, those for the extended letter. It will be observed that one side of each form is divided into four equal parts, each appropriated to certain letters 12

The Manufacturer and Builder. Hints for Sign-Painters. As simple and ~~asy as it may seem to be able to let- ter a sign properly, it must be admitted that there are but few that are well lettered, and so made as to be attractive both in color and style of letter. The conviction is forced upon the observer that the majority of signs are overdone, donstrained, and evidently de- signed in very bad taste. In addition to all conceiva- ble forms and shapes of signsand among these forms we may enumerate long, round, square, oval, trian- gular, hexagonal, polygonal, scroll, stellated, prisma- tic, animal, and floral-shapedwe observe as many forms and styles of letter, each style being somewhat peculiar in itself, and in some degree original with the artist who desigr~ed it. We are not apt to notice small signs unless we are seeking particularly for them, or are interested in something connected therewith unusually large and largely lettered signs escape our observa- tion by being so excessively obvious. Scanty-lettered signs we do not often care to read the second time, as we get but little satisfaction by so doing, while pro- fusely lettered ones we do not read, for it is often too tedious. The signs that are generally remembered are those that are in size neither too large nor too small, neither gaudy nor tame in their coloring, neither scanty nor profuse in their lettering, and that give, in plain letters and in a few words, the information they have to convey. A sign of this character carries a correct business cast with it, and as we enter the establishment we feel quite sure that the proceedings and business within will harmonize with the 8igm with- out. A plain and direct business should be represented by a plain parallelogram form of sign, with a plain, bold lett~r that seems to tell you that things are done as they should be, and indicative that a balance-sheet is made out at the end of each financial year. When we see signs that are overlarge, or, on the other hand, too small, we are apt to imagine that the trade of the establishment to which they belong corresponds to their respective peculiarities. There seems to be a growing indication of press- ing the forms of masculine and female figures into service, and making them perform the duties of the signboard. The Goddess of Liberty, with outstretched arm resting on her star-studded shield, resplendent with stars and stripes of an indefinite number, points to the oyster-cellar, or the retreat where flows the lager; the American eagle, in brass and Dutch- leaf gold, is perched over the portals of the entrance where pinchbeck watches are sold. Male and female aborigines, coarsely painted with vermilion or be- daubed with burnt amber, stolid, ill-shaped, and nearly nude, together with the sooty African, the swarthy Turk, the kilted Highlander, and fun-loving Punch, dressed in gaudy, nondescript irobes, tell us where the scented maccaboy and other snuffs, or the choicest varieties of the weed, may be obtained. But good taste admits that the majority of these forms are but caricatures of true signs. They are not at all intended to represent the word business in a true, substantial, or commercial sense. It may not be out of place here to make a few re- marks relative to show-cards, since they are nothing but miniature signs. They embody as many charac- teristics as the permanent signboard, and are as much admired or condemned by the lovers of good taste. As the show-card, or even the business card, is an isolated piece of work, harmony of typographic group- ing ~nust be sought for. As in a sign, a crowding to- gether of the words produces confusion, and too much blank space causes a painful contrast between the color of the card and that of the ink. Moreover, an unequal gradation of the sizes of the letters, or the lines unduly spaced, is equally distasteful. As we hastily look at a business card, we expect to see at a glance the name of the firm it represents, as well as their business. Like a business sign, a business card should be printed in a plain, bold letter, the name of the business being the most conspicuous, as if it were not afraid of being inspected. The names of the firm should also be bold, yet not too prominent, as if modesty was one of their peculiar characteristics. Then the place where their business is conducted should be in a smaller letter, as if not pushing itself too much in your way, and the necessary details should thereafter follow in a plain letter, corresponding with the other general features of it. Like signs, the card that is the most admired is plain, of medium size, in conspicuous print, concisely worded, and with an even margin areund the edges, giving relief to the reading matter, which it incloses like a frame. Large-sized cards we do not so often notice or keep, unless we are particularly interested in them, especially if they are profusely lettered; we lay them aside until we feel that we have leisure to peruse them. Small cards we notice but little, as their dwarf proportions seem to carry an air of a limited business. It is more to the distorted and ill-proportioned ap- pearance of letters as seen upon signs and show-cards that we would call attention. A person who has a love for beautiful and correct letters can not be other- wise than pained at such distorted ones. Probably there is no art more difficult of attainment, and one in which so few persons are proficient, as that of making letters of the style called Roman; yet this letter is the one in which our books and papers are printed, and the one most commonly presented to the eye. However perfectly formed these letters may be when shaped by the art of the die-sinker, as seen in the impression produced by printing-types, never- theless, sign-boards that at every step meet our eyes attest that upon them are many unsuccessful attempts to form well-proportioned letters. Among a few of ~he faults that are evident we will iuention that the letters A, V. and W often encroach upon each others premises, and if a vertical line were drawn between two of them, more or less of each letter would be cut off. That each letter must be inclosed within a space determined by right angles, as is seen upon a printers type, seems not to have entered the mind of the artist. It is nothing uncommon to see a total disregard of the rules of proportion in reference to the space that letters should occupy. The Roman letter, as employed by sign-painters, is capable of being extended from its common width, and is also capable of being condensed, and is known by the terms of common, extended, and condensed letter, each having the same height, but different widths. These three proportions are amply sufficient for ordi- udry signs. The makers of type have extra-extended and also extra-condensed letters, but these forms are not often called into requisition by the sign or show- card painter. It will be observed that, when capital letters are placed in the order of their width, the letter I occupies the least space ; J is a little wider; C, L, 5, and Z occupy the third place; 0 and Q, the fourth; B, D, E, F, P, T, and & , the fifth; G, U, V, and Y, the sixth; A, K, R, and X, the seventh; H and N, the eighth; M, the ninth; and W, the tenth; ~ and ~ occupy a space between the ninth and tenth spaces. This division of the alphabet may be of . assistance to those who are sometimes at a loss what proportional width to give letters when grouped together. We see, then, if the letter I be taken as one width, A and the others of the seventh group occupy each twice the width of I; the third, or C group, one and a half. By spacing an alphabet with dividers, the cor- rect width that spaces of each division should occupy can be readily and correctly ascertained. Of the small letters, or, as they are termed by printers, the lower-case letters, we notice that i, j, and 1 are the least and the same in width; f and t then follow, being a little wider; the third space is filled by c, e, o, r, and s; the fourth space is occupied by a, b, d, g, p, q, and z; the fifth by h, k, n, ir, v, x, and y; the seventh by m and w. The space occupied by if, fi, fi, ~, and ce is the same as that of the capital letters B, D, and others of that series, which also . very nearly corre- sponds to the small letters h, k, etc. The space occu- pied by ffi and ifi is the same as that required for M. The dollar mark, $, has the same width as the letter J. In a comparison of the small letters with the capitals, we find that i, j, and 1 are less in width than the capital I, which very nearly corresponds fo the space occupied by f and t. The third space of the small letters falls between that of I and J, while the fourth is the same as that of the capital J. The small letters h, k, etc., of the fifth space are the same as the space of the capitals C, L, 5, and Z. The figures, or Arabic numerals, may be divided into four groups. The figure 1 is first, occupyin~ the least space. The figure 7 is next in width; then fol- low 2, 3, 4, 5, 6, 5, and 9, and lastly the 0, generally made a little wider. The figures 1, 7, and the letter I occupy the same width; with the exception of the 0, which occupies the same space as L, 5, and Z, the other figures are of the same width as the capital let- ter J. If one would form well-proportioned letters, he should divide the alphabet into groups in the order we have indicated. Since the capital I occupies the least. space, it may be taken as a .standard. The eye and judgment, assisted by this scale of widths, will enable any person to obtain a very good idea of the space the others should occupy. In addition to proportioning the width, it will be observed that icany letters, as A, M, N, V, W, X, Y~ and Z, are made up in part of oblique lines. It will: be further observed that the angles and lines of A. differ from those of K, and both A and K differ in: their angles from X and W. A closer examination of well-proportioned letters xviii show that the inclined~ portions of A, M, and V have the same angles, those of X,Y, and Z are similar, and K and W, the two remain- ing letters, are made in part with unlike oblique lines, and also differing from the others mentioned. There are, therefore, but four angles in all these letters, and if they could be determined, there would then be an easy rule governing their formation. Taste and circumstances determine the width of the common Roman, the extended, or condensed letter. As they . thus differ, the oblique lines of the letters so formed also differ. To approximate to the proper angles for each of the three kinds, let one provide himself with three pieces of thin board, metal, or even thick paper, made with one side and the bottom at right angles to each other; the other side is cut with four angles, as seen in the figures. Fig. 1 shows the angles for the condensed letter; Fig; 2, those for the common Roman letter; and Fig. 3, those for the extended letter. It will be observed that one side of each form is divided into four equal parts, each appropriated to certain letters 12 The Manufacturer and Builder. and varying in angle from its neighbor. The lower division gives the oblique lines of the W, the second those of A, M, N, and V, the third those of X, Y, and Z, and the fourth K. No exact guide can be given for these angles; as before remarked, taste and judgment must decide them. One can measure the angles of some good alphabet and be governed by them in mak- ing his angles. To use these instruments, place the bottom portion upon a line drawn beneath the letters to be made, or the back can be similiarly placed upon a vertical line, an~ the angles formed from the appropriate divisions. The draughtsman can use his T-square or parallel rule, which is adjusted so as to bring the divisions re- quired between the lines forming the top and bottom of the letters, and make the lines as he would upon the beveled side of a triangular set-square. To persons who have difficulty in making letters upon signs, plans, or drawings, the hints above given may prove of essential service, and although we have given but a hint~~ for an approximation to good letters, nevertheless, to the ingenious, to those who pride themselves upon a uniform style of letter, this hint will be acceptable, and can be c~rried out with the most satisfactory results. Imitation-Marble. IT can not be gainsaid that a quality of imitation- marble, or HeUenenstein, as it is sometimes called by the German, is now being produced in the arts, which, in comparison to native marble, comes up very nearly to the highest point in the way of perfection. Indeed, in the old Roman times the most beautiful structures were ornamented in their interior parts with pieces of marble which consisted commonly of sand, lime, and gypsum, and which even yet exist. Bttt in order the more to perfect this art, it was necessary that one of the many secrets of nature should be won from her keeping. Some two years ago, a manufacturer in Cassel, of the name of THIEL, succeeded in producing an artificial stone, knowm under the above name, which is said to exceed in its excellences any that have, been made heretofore. It is prepared by means of chemico-physical methods, which are known only to thediscoverer and a few manu- facturers. The writer of an article iii the Polytech- nisehes Notirblatt, to whom we are indebted for these facts, states thr~ in one manufactory large four-corner- ed slabs are made, having a length of ten feet, width of five feet, and a thickness of one foot. After one day of drying, under the influence of an ordinary tempera- ture, these slabs are cut into smaller ones, out of which plates or slabs for the tops of washstands, tables, man- tels, etc., are manufactured. But above all else, however, this material is adapted to building and decorative purposes. It is stated, moreover, that the castle in Brunswick, Germany, which was very much injured by fire not long ago, is to be ornamented with this imitation-marble, as also the new music-hall in Hamburg. Besides these uses, very tasteful mosaic-work can be made from it. This is done by first sketching the figure or figures upon the stone; they are next neatly cut out with fine instru- men~s, and then, finally, filled in again with the same artiricial mass of the desired shades of color. The stir- face is then polished as though it were native marble, until it has taken on a perfect lustre, In so far as the name Hellenemstein is concerned, it may be remarked that the nature of the mass is such that one can imitate, even to the point of decep- tion, the most excellent and purest kinds of marble ob- tained from the Hellenic Mountains of Greece. Nor, as giving rise to quite a new branch of industry, does the imitation, in any respect, fall far behind those rare kinds of Grecian native marble. Slabs for building purposes, cornice-work, etc., are manufactured in large blocks. These are afterwards further wrought by means of steam power, under the circular saw and the planing machine; then, finally, they come into the hands of the worker, who finishes them in accordance with the purposes for which they are designed. Common Mortar. LIME is produced in almost every part of the civil- ized world by burning either limestone or shells. This burning process brings about the expulsion of carbonic acid in the state of gaslimestone and shells being nothing but a carbonate of lime, with some or- ganic impurities which are also driven off by the heat; and often small amounts of silica, alumina, and mag- nesia, which combine during the process of burning with a small portion of the lime. The resulting pro- ducts of the burning or calcining is commonly called quicklime, which is, in fact, the oxide of a metal called calcium. This quicklime has a very strong affinity for carbonic acid, and also for water. It will absorb them from the atmosphere when left exposed, and thus quickly deteriorate. The carbonic acid is much more injurious than the water. It deadens the lime, so to speak. When mixed with water so as to form a pasty mass, it may be kept for some time. When this pasty mass is still further mixed with sand, it forms ordinary mortar. Simple lime as a paste hardens as well as mortar, but it forms only a loose mass, of too weak a consistency to bind the stones of a wall together. A striking illus- tration of this is found in the ruins of Fort Putnum, situated on the top of a hill behind West-Point, on the Hudson River. The mortar there is all crumbling to dust, and the stones are falling apart, evidently because no sand, or an insufficient amount of it, was used in the preparation of the mortar, probably on account of the scarcity of it on the top of this granite rock. When the quantity of sand in mortar is sufficient, it hardens gradually in its place between the bricks until it is as solid and firm as the original limestone. It ad- heres very strongly to the bricks, and then cements them together. Pure lime paste without sand will only cement in very thin layers between two smooth stones. Where, however, the stones are irregular, they consequently offer many thick places in the layers of lime paste. It is necessary, therefore, that these places should be interspersed with points of attachment for the lime. These are found in sand, coarse gravel, and irregular small stones. Much sand in the mortar is good, public opinion to the contrary notwithstand- ing. In fact, as little lime as possible should be used; and, as a rule, only as much lime paste should be mixed with sand as will fill up the interstices of the sand; in other words, as much as the sand will take up without increasing its bulk. This is found to be ac- complished by using six pounds of sand for every one pound of lime; or, in bulk, three to four cubic feet of sand for every cubic foot of lime paste. Good. fat lime will stand more sand; poor sandy lime less, sometimes only two cubic foot for every one cubic foot of lime. The sand of course -must be pure. When it contains clay, more can be used, in order to make a consistent mortar, but it is always of inferior quality. Sand con- taining humus, bog-earth, peat, or other organic re- mains, is entirely unfit for mortar. Although mortar sets sufficiently in a few days or weeks to enable a wall to withstand pressure, yet the hardening process goes on so slowly that it attains its maximum degree of hardness only after years or even after many centuries of time have elapsed. In the last case, the wall becomes to all intents and pur- poses as solid as if made of one single piece of stone. The apparent superiority of mortar in olden times over that of the present day must be due solely to the long time it has had to harden, since it has been proved that no difference exists as regards the nature of the ingredients employed. When the French army, some seventy-five years ago, were guilty of the vandalism of destroying the beautifui castle of Heidell1~rg, in Ger- many, they placed gunpowder in an old square tower, built about the year 1100. The result was that the whole tower was displaced in one single piece. It now stands very much inclined, and shows the effects of the explosion only by one large crack, running from top to bottom. In a building of recent structure, where the effects of time would not have been suffi- ~ient to have hardened the mortar, scarcely one stotie would have remained attached to another when sub- mitted to such a severe trial. It is certain that many buildings erected at present will stand the test of time, and be inherited by posterity as models of solid masonry, just as those of the middle ages are now by us. The inferior ones will crumble and be unknown to them, just as the inferior ones of olden times have crumbled and are now unknown to us. This hardening of mortar in the course of ages is so difficult to explain, on chemical principles, that it is even denied by some, and asserted that, as soon as the lime has absorbed all the carbonic acid from the at- mosphere it is capable of, the hardening process is finished; and this, it is said, takes place in a single season. Experiments, however, have shown that the mortar in the interior parts of walls built three hun. dred years ago was still caustic, or, in other words, had not been changed into carbonate of lime, and that part of the lime had combined with the silica, and formed a silicate of lime. Experiments made for the purpose prove that, when quicklime is mixed with sand, the amount of silicate of lime which does not at first exist, and which is soluble in hydrochloric acid, increases continually in the course of time, and in one week amounts to one half per cent; in five weeks to one per cent; in ten months to seven pe~ cent. As, however, mortar will harden when, instead of si- licious limestone, sand is used, the hardening must be due also to other than mere chemical causes. One of the most important among these is probably the crys- tallization of the hydrate of lime, which takes place slowly under the influence of the periodically moist and dry states of the atmosphere. The hardening of mortar is therefore probably due to the three causes mentioned combined, namely, the absorption of carbon- ic acid, the slow combination of lime with the silex, the consequent increase of the amount of silicate of lime, and, lastly, the crystallization of the hydrate of lime. The absorption of carbonic acid induces a separation of an equivalent amount of water from the hydrate of lime, and is the cause of the moisture of newly-built walls. As one square yard of a coating of mortar one inch thick weighs nearly one hundred pounds and contains four pounds of lime, with which more than one pound of water is combined, in a room with a plastered surface of forty square yards, this will amount to some forty pounds. This will all be given out, and the process go on until the quick-lime has combined with the carbonic acid from the atmosphere. Sometimes, when the water thus given out dries quickly upon such newly-built walls, effiorescences are observed. They have been analyzed by VOGEL and KIJHLMAN in Germany, and found to consist of sulphate of soda, carbonate of soda, common salt, carbonate of potassa, and chloride of potassium. It is probable that some of these alkalies were taken up by the lime- stone from the ashes of the fuel used in burning the lime. New Paint for Floors. WE learn that a new kind of paint, especially good for floors, is made out of water-glass. It unites not only the qualities of beauty and durability, but is also advantageous as a means of protection against the ac- tion of fire. In order to lay on a covering of this paint, first of all the floor is neatly cleaned, then any cracks or crevices between the boards that may exist are luted with a thick dough made of water-glass and pal- verized chalk or gypsum. By means of a stiff brush a coating of water-glass of the consistency, say, of syrup. is then spread over the floor. Again in the same man- ner a second coating is laid on, consi sting of water- glass mixed with the desired color. It must, however be a mineral color, from the fact that the alkalies of the water-glass commonly decompose vegetable colors. This coating having become dry, other layers of water glass may be thereafter given, until the tioor has taken on the required lustrous appearance. In order to give the surface a brightness indicative of polish, it ~s ground off a little, oUed, am~ ~reu.ghly dried. In 13

The Manufacturer and Builder. and varying in angle from its neighbor. The lower division gives the oblique lines of the W, the second those of A, M, N, and V, the third those of X, Y, and Z, and the fourth K. No exact guide can be given for these angles; as before remarked, taste and judgment must decide them. One can measure the angles of some good alphabet and be governed by them in mak- ing his angles. To use these instruments, place the bottom portion upon a line drawn beneath the letters to be made, or the back can be similiarly placed upon a vertical line, an~ the angles formed from the appropriate divisions. The draughtsman can use his T-square or parallel rule, which is adjusted so as to bring the divisions re- quired between the lines forming the top and bottom of the letters, and make the lines as he would upon the beveled side of a triangular set-square. To persons who have difficulty in making letters upon signs, plans, or drawings, the hints above given may prove of essential service, and although we have given but a hint~~ for an approximation to good letters, nevertheless, to the ingenious, to those who pride themselves upon a uniform style of letter, this hint will be acceptable, and can be c~rried out with the most satisfactory results. Imitation-Marble. IT can not be gainsaid that a quality of imitation- marble, or HeUenenstein, as it is sometimes called by the German, is now being produced in the arts, which, in comparison to native marble, comes up very nearly to the highest point in the way of perfection. Indeed, in the old Roman times the most beautiful structures were ornamented in their interior parts with pieces of marble which consisted commonly of sand, lime, and gypsum, and which even yet exist. Bttt in order the more to perfect this art, it was necessary that one of the many secrets of nature should be won from her keeping. Some two years ago, a manufacturer in Cassel, of the name of THIEL, succeeded in producing an artificial stone, knowm under the above name, which is said to exceed in its excellences any that have, been made heretofore. It is prepared by means of chemico-physical methods, which are known only to thediscoverer and a few manu- facturers. The writer of an article iii the Polytech- nisehes Notirblatt, to whom we are indebted for these facts, states thr~ in one manufactory large four-corner- ed slabs are made, having a length of ten feet, width of five feet, and a thickness of one foot. After one day of drying, under the influence of an ordinary tempera- ture, these slabs are cut into smaller ones, out of which plates or slabs for the tops of washstands, tables, man- tels, etc., are manufactured. But above all else, however, this material is adapted to building and decorative purposes. It is stated, moreover, that the castle in Brunswick, Germany, which was very much injured by fire not long ago, is to be ornamented with this imitation-marble, as also the new music-hall in Hamburg. Besides these uses, very tasteful mosaic-work can be made from it. This is done by first sketching the figure or figures upon the stone; they are next neatly cut out with fine instru- men~s, and then, finally, filled in again with the same artiricial mass of the desired shades of color. The stir- face is then polished as though it were native marble, until it has taken on a perfect lustre, In so far as the name Hellenemstein is concerned, it may be remarked that the nature of the mass is such that one can imitate, even to the point of decep- tion, the most excellent and purest kinds of marble ob- tained from the Hellenic Mountains of Greece. Nor, as giving rise to quite a new branch of industry, does the imitation, in any respect, fall far behind those rare kinds of Grecian native marble. Slabs for building purposes, cornice-work, etc., are manufactured in large blocks. These are afterwards further wrought by means of steam power, under the circular saw and the planing machine; then, finally, they come into the hands of the worker, who finishes them in accordance with the purposes for which they are designed. Common Mortar. LIME is produced in almost every part of the civil- ized world by burning either limestone or shells. This burning process brings about the expulsion of carbonic acid in the state of gaslimestone and shells being nothing but a carbonate of lime, with some or- ganic impurities which are also driven off by the heat; and often small amounts of silica, alumina, and mag- nesia, which combine during the process of burning with a small portion of the lime. The resulting pro- ducts of the burning or calcining is commonly called quicklime, which is, in fact, the oxide of a metal called calcium. This quicklime has a very strong affinity for carbonic acid, and also for water. It will absorb them from the atmosphere when left exposed, and thus quickly deteriorate. The carbonic acid is much more injurious than the water. It deadens the lime, so to speak. When mixed with water so as to form a pasty mass, it may be kept for some time. When this pasty mass is still further mixed with sand, it forms ordinary mortar. Simple lime as a paste hardens as well as mortar, but it forms only a loose mass, of too weak a consistency to bind the stones of a wall together. A striking illus- tration of this is found in the ruins of Fort Putnum, situated on the top of a hill behind West-Point, on the Hudson River. The mortar there is all crumbling to dust, and the stones are falling apart, evidently because no sand, or an insufficient amount of it, was used in the preparation of the mortar, probably on account of the scarcity of it on the top of this granite rock. When the quantity of sand in mortar is sufficient, it hardens gradually in its place between the bricks until it is as solid and firm as the original limestone. It ad- heres very strongly to the bricks, and then cements them together. Pure lime paste without sand will only cement in very thin layers between two smooth stones. Where, however, the stones are irregular, they consequently offer many thick places in the layers of lime paste. It is necessary, therefore, that these places should be interspersed with points of attachment for the lime. These are found in sand, coarse gravel, and irregular small stones. Much sand in the mortar is good, public opinion to the contrary notwithstand- ing. In fact, as little lime as possible should be used; and, as a rule, only as much lime paste should be mixed with sand as will fill up the interstices of the sand; in other words, as much as the sand will take up without increasing its bulk. This is found to be ac- complished by using six pounds of sand for every one pound of lime; or, in bulk, three to four cubic feet of sand for every cubic foot of lime paste. Good. fat lime will stand more sand; poor sandy lime less, sometimes only two cubic foot for every one cubic foot of lime. The sand of course -must be pure. When it contains clay, more can be used, in order to make a consistent mortar, but it is always of inferior quality. Sand con- taining humus, bog-earth, peat, or other organic re- mains, is entirely unfit for mortar. Although mortar sets sufficiently in a few days or weeks to enable a wall to withstand pressure, yet the hardening process goes on so slowly that it attains its maximum degree of hardness only after years or even after many centuries of time have elapsed. In the last case, the wall becomes to all intents and pur- poses as solid as if made of one single piece of stone. The apparent superiority of mortar in olden times over that of the present day must be due solely to the long time it has had to harden, since it has been proved that no difference exists as regards the nature of the ingredients employed. When the French army, some seventy-five years ago, were guilty of the vandalism of destroying the beautifui castle of Heidell1~rg, in Ger- many, they placed gunpowder in an old square tower, built about the year 1100. The result was that the whole tower was displaced in one single piece. It now stands very much inclined, and shows the effects of the explosion only by one large crack, running from top to bottom. In a building of recent structure, where the effects of time would not have been suffi- ~ient to have hardened the mortar, scarcely one stotie would have remained attached to another when sub- mitted to such a severe trial. It is certain that many buildings erected at present will stand the test of time, and be inherited by posterity as models of solid masonry, just as those of the middle ages are now by us. The inferior ones will crumble and be unknown to them, just as the inferior ones of olden times have crumbled and are now unknown to us. This hardening of mortar in the course of ages is so difficult to explain, on chemical principles, that it is even denied by some, and asserted that, as soon as the lime has absorbed all the carbonic acid from the at- mosphere it is capable of, the hardening process is finished; and this, it is said, takes place in a single season. Experiments, however, have shown that the mortar in the interior parts of walls built three hun. dred years ago was still caustic, or, in other words, had not been changed into carbonate of lime, and that part of the lime had combined with the silica, and formed a silicate of lime. Experiments made for the purpose prove that, when quicklime is mixed with sand, the amount of silicate of lime which does not at first exist, and which is soluble in hydrochloric acid, increases continually in the course of time, and in one week amounts to one half per cent; in five weeks to one per cent; in ten months to seven pe~ cent. As, however, mortar will harden when, instead of si- licious limestone, sand is used, the hardening must be due also to other than mere chemical causes. One of the most important among these is probably the crys- tallization of the hydrate of lime, which takes place slowly under the influence of the periodically moist and dry states of the atmosphere. The hardening of mortar is therefore probably due to the three causes mentioned combined, namely, the absorption of carbon- ic acid, the slow combination of lime with the silex, the consequent increase of the amount of silicate of lime, and, lastly, the crystallization of the hydrate of lime. The absorption of carbonic acid induces a separation of an equivalent amount of water from the hydrate of lime, and is the cause of the moisture of newly-built walls. As one square yard of a coating of mortar one inch thick weighs nearly one hundred pounds and contains four pounds of lime, with which more than one pound of water is combined, in a room with a plastered surface of forty square yards, this will amount to some forty pounds. This will all be given out, and the process go on until the quick-lime has combined with the carbonic acid from the atmosphere. Sometimes, when the water thus given out dries quickly upon such newly-built walls, effiorescences are observed. They have been analyzed by VOGEL and KIJHLMAN in Germany, and found to consist of sulphate of soda, carbonate of soda, common salt, carbonate of potassa, and chloride of potassium. It is probable that some of these alkalies were taken up by the lime- stone from the ashes of the fuel used in burning the lime. New Paint for Floors. WE learn that a new kind of paint, especially good for floors, is made out of water-glass. It unites not only the qualities of beauty and durability, but is also advantageous as a means of protection against the ac- tion of fire. In order to lay on a covering of this paint, first of all the floor is neatly cleaned, then any cracks or crevices between the boards that may exist are luted with a thick dough made of water-glass and pal- verized chalk or gypsum. By means of a stiff brush a coating of water-glass of the consistency, say, of syrup. is then spread over the floor. Again in the same man- ner a second coating is laid on, consi sting of water- glass mixed with the desired color. It must, however be a mineral color, from the fact that the alkalies of the water-glass commonly decompose vegetable colors. This coating having become dry, other layers of water glass may be thereafter given, until the tioor has taken on the required lustrous appearance. In order to give the surface a brightness indicative of polish, it ~s ground off a little, oUed, am~ ~reu.ghly dried. In 13

The Manufacturer and Builder. and varying in angle from its neighbor. The lower division gives the oblique lines of the W, the second those of A, M, N, and V, the third those of X, Y, and Z, and the fourth K. No exact guide can be given for these angles; as before remarked, taste and judgment must decide them. One can measure the angles of some good alphabet and be governed by them in mak- ing his angles. To use these instruments, place the bottom portion upon a line drawn beneath the letters to be made, or the back can be similiarly placed upon a vertical line, an~ the angles formed from the appropriate divisions. The draughtsman can use his T-square or parallel rule, which is adjusted so as to bring the divisions re- quired between the lines forming the top and bottom of the letters, and make the lines as he would upon the beveled side of a triangular set-square. To persons who have difficulty in making letters upon signs, plans, or drawings, the hints above given may prove of essential service, and although we have given but a hint~~ for an approximation to good letters, nevertheless, to the ingenious, to those who pride themselves upon a uniform style of letter, this hint will be acceptable, and can be c~rried out with the most satisfactory results. Imitation-Marble. IT can not be gainsaid that a quality of imitation- marble, or HeUenenstein, as it is sometimes called by the German, is now being produced in the arts, which, in comparison to native marble, comes up very nearly to the highest point in the way of perfection. Indeed, in the old Roman times the most beautiful structures were ornamented in their interior parts with pieces of marble which consisted commonly of sand, lime, and gypsum, and which even yet exist. Bttt in order the more to perfect this art, it was necessary that one of the many secrets of nature should be won from her keeping. Some two years ago, a manufacturer in Cassel, of the name of THIEL, succeeded in producing an artificial stone, knowm under the above name, which is said to exceed in its excellences any that have, been made heretofore. It is prepared by means of chemico-physical methods, which are known only to thediscoverer and a few manu- facturers. The writer of an article iii the Polytech- nisehes Notirblatt, to whom we are indebted for these facts, states thr~ in one manufactory large four-corner- ed slabs are made, having a length of ten feet, width of five feet, and a thickness of one foot. After one day of drying, under the influence of an ordinary tempera- ture, these slabs are cut into smaller ones, out of which plates or slabs for the tops of washstands, tables, man- tels, etc., are manufactured. But above all else, however, this material is adapted to building and decorative purposes. It is stated, moreover, that the castle in Brunswick, Germany, which was very much injured by fire not long ago, is to be ornamented with this imitation-marble, as also the new music-hall in Hamburg. Besides these uses, very tasteful mosaic-work can be made from it. This is done by first sketching the figure or figures upon the stone; they are next neatly cut out with fine instru- men~s, and then, finally, filled in again with the same artiricial mass of the desired shades of color. The stir- face is then polished as though it were native marble, until it has taken on a perfect lustre, In so far as the name Hellenemstein is concerned, it may be remarked that the nature of the mass is such that one can imitate, even to the point of decep- tion, the most excellent and purest kinds of marble ob- tained from the Hellenic Mountains of Greece. Nor, as giving rise to quite a new branch of industry, does the imitation, in any respect, fall far behind those rare kinds of Grecian native marble. Slabs for building purposes, cornice-work, etc., are manufactured in large blocks. These are afterwards further wrought by means of steam power, under the circular saw and the planing machine; then, finally, they come into the hands of the worker, who finishes them in accordance with the purposes for which they are designed. Common Mortar. LIME is produced in almost every part of the civil- ized world by burning either limestone or shells. This burning process brings about the expulsion of carbonic acid in the state of gaslimestone and shells being nothing but a carbonate of lime, with some or- ganic impurities which are also driven off by the heat; and often small amounts of silica, alumina, and mag- nesia, which combine during the process of burning with a small portion of the lime. The resulting pro- ducts of the burning or calcining is commonly called quicklime, which is, in fact, the oxide of a metal called calcium. This quicklime has a very strong affinity for carbonic acid, and also for water. It will absorb them from the atmosphere when left exposed, and thus quickly deteriorate. The carbonic acid is much more injurious than the water. It deadens the lime, so to speak. When mixed with water so as to form a pasty mass, it may be kept for some time. When this pasty mass is still further mixed with sand, it forms ordinary mortar. Simple lime as a paste hardens as well as mortar, but it forms only a loose mass, of too weak a consistency to bind the stones of a wall together. A striking illus- tration of this is found in the ruins of Fort Putnum, situated on the top of a hill behind West-Point, on the Hudson River. The mortar there is all crumbling to dust, and the stones are falling apart, evidently because no sand, or an insufficient amount of it, was used in the preparation of the mortar, probably on account of the scarcity of it on the top of this granite rock. When the quantity of sand in mortar is sufficient, it hardens gradually in its place between the bricks until it is as solid and firm as the original limestone. It ad- heres very strongly to the bricks, and then cements them together. Pure lime paste without sand will only cement in very thin layers between two smooth stones. Where, however, the stones are irregular, they consequently offer many thick places in the layers of lime paste. It is necessary, therefore, that these places should be interspersed with points of attachment for the lime. These are found in sand, coarse gravel, and irregular small stones. Much sand in the mortar is good, public opinion to the contrary notwithstand- ing. In fact, as little lime as possible should be used; and, as a rule, only as much lime paste should be mixed with sand as will fill up the interstices of the sand; in other words, as much as the sand will take up without increasing its bulk. This is found to be ac- complished by using six pounds of sand for every one pound of lime; or, in bulk, three to four cubic feet of sand for every cubic foot of lime paste. Good. fat lime will stand more sand; poor sandy lime less, sometimes only two cubic foot for every one cubic foot of lime. The sand of course -must be pure. When it contains clay, more can be used, in order to make a consistent mortar, but it is always of inferior quality. Sand con- taining humus, bog-earth, peat, or other organic re- mains, is entirely unfit for mortar. Although mortar sets sufficiently in a few days or weeks to enable a wall to withstand pressure, yet the hardening process goes on so slowly that it attains its maximum degree of hardness only after years or even after many centuries of time have elapsed. In the last case, the wall becomes to all intents and pur- poses as solid as if made of one single piece of stone. The apparent superiority of mortar in olden times over that of the present day must be due solely to the long time it has had to harden, since it has been proved that no difference exists as regards the nature of the ingredients employed. When the French army, some seventy-five years ago, were guilty of the vandalism of destroying the beautifui castle of Heidell1~rg, in Ger- many, they placed gunpowder in an old square tower, built about the year 1100. The result was that the whole tower was displaced in one single piece. It now stands very much inclined, and shows the effects of the explosion only by one large crack, running from top to bottom. In a building of recent structure, where the effects of time would not have been suffi- ~ient to have hardened the mortar, scarcely one stotie would have remained attached to another when sub- mitted to such a severe trial. It is certain that many buildings erected at present will stand the test of time, and be inherited by posterity as models of solid masonry, just as those of the middle ages are now by us. The inferior ones will crumble and be unknown to them, just as the inferior ones of olden times have crumbled and are now unknown to us. This hardening of mortar in the course of ages is so difficult to explain, on chemical principles, that it is even denied by some, and asserted that, as soon as the lime has absorbed all the carbonic acid from the at- mosphere it is capable of, the hardening process is finished; and this, it is said, takes place in a single season. Experiments, however, have shown that the mortar in the interior parts of walls built three hun. dred years ago was still caustic, or, in other words, had not been changed into carbonate of lime, and that part of the lime had combined with the silica, and formed a silicate of lime. Experiments made for the purpose prove that, when quicklime is mixed with sand, the amount of silicate of lime which does not at first exist, and which is soluble in hydrochloric acid, increases continually in the course of time, and in one week amounts to one half per cent; in five weeks to one per cent; in ten months to seven pe~ cent. As, however, mortar will harden when, instead of si- licious limestone, sand is used, the hardening must be due also to other than mere chemical causes. One of the most important among these is probably the crys- tallization of the hydrate of lime, which takes place slowly under the influence of the periodically moist and dry states of the atmosphere. The hardening of mortar is therefore probably due to the three causes mentioned combined, namely, the absorption of carbon- ic acid, the slow combination of lime with the silex, the consequent increase of the amount of silicate of lime, and, lastly, the crystallization of the hydrate of lime. The absorption of carbonic acid induces a separation of an equivalent amount of water from the hydrate of lime, and is the cause of the moisture of newly-built walls. As one square yard of a coating of mortar one inch thick weighs nearly one hundred pounds and contains four pounds of lime, with which more than one pound of water is combined, in a room with a plastered surface of forty square yards, this will amount to some forty pounds. This will all be given out, and the process go on until the quick-lime has combined with the carbonic acid from the atmosphere. Sometimes, when the water thus given out dries quickly upon such newly-built walls, effiorescences are observed. They have been analyzed by VOGEL and KIJHLMAN in Germany, and found to consist of sulphate of soda, carbonate of soda, common salt, carbonate of potassa, and chloride of potassium. It is probable that some of these alkalies were taken up by the lime- stone from the ashes of the fuel used in burning the lime. New Paint for Floors. WE learn that a new kind of paint, especially good for floors, is made out of water-glass. It unites not only the qualities of beauty and durability, but is also advantageous as a means of protection against the ac- tion of fire. In order to lay on a covering of this paint, first of all the floor is neatly cleaned, then any cracks or crevices between the boards that may exist are luted with a thick dough made of water-glass and pal- verized chalk or gypsum. By means of a stiff brush a coating of water-glass of the consistency, say, of syrup. is then spread over the floor. Again in the same man- ner a second coating is laid on, consi sting of water- glass mixed with the desired color. It must, however be a mineral color, from the fact that the alkalies of the water-glass commonly decompose vegetable colors. This coating having become dry, other layers of water glass may be thereafter given, until the tioor has taken on the required lustrous appearance. In order to give the surface a brightness indicative of polish, it ~s ground off a little, oUed, am~ ~reu.ghly dried. In 13

The Manufacturer and Builder. and varying in angle from its neighbor. The lower division gives the oblique lines of the W, the second those of A, M, N, and V, the third those of X, Y, and Z, and the fourth K. No exact guide can be given for these angles; as before remarked, taste and judgment must decide them. One can measure the angles of some good alphabet and be governed by them in mak- ing his angles. To use these instruments, place the bottom portion upon a line drawn beneath the letters to be made, or the back can be similiarly placed upon a vertical line, an~ the angles formed from the appropriate divisions. The draughtsman can use his T-square or parallel rule, which is adjusted so as to bring the divisions re- quired between the lines forming the top and bottom of the letters, and make the lines as he would upon the beveled side of a triangular set-square. To persons who have difficulty in making letters upon signs, plans, or drawings, the hints above given may prove of essential service, and although we have given but a hint~~ for an approximation to good letters, nevertheless, to the ingenious, to those who pride themselves upon a uniform style of letter, this hint will be acceptable, and can be c~rried out with the most satisfactory results. Imitation-Marble. IT can not be gainsaid that a quality of imitation- marble, or HeUenenstein, as it is sometimes called by the German, is now being produced in the arts, which, in comparison to native marble, comes up very nearly to the highest point in the way of perfection. Indeed, in the old Roman times the most beautiful structures were ornamented in their interior parts with pieces of marble which consisted commonly of sand, lime, and gypsum, and which even yet exist. Bttt in order the more to perfect this art, it was necessary that one of the many secrets of nature should be won from her keeping. Some two years ago, a manufacturer in Cassel, of the name of THIEL, succeeded in producing an artificial stone, knowm under the above name, which is said to exceed in its excellences any that have, been made heretofore. It is prepared by means of chemico-physical methods, which are known only to thediscoverer and a few manu- facturers. The writer of an article iii the Polytech- nisehes Notirblatt, to whom we are indebted for these facts, states thr~ in one manufactory large four-corner- ed slabs are made, having a length of ten feet, width of five feet, and a thickness of one foot. After one day of drying, under the influence of an ordinary tempera- ture, these slabs are cut into smaller ones, out of which plates or slabs for the tops of washstands, tables, man- tels, etc., are manufactured. But above all else, however, this material is adapted to building and decorative purposes. It is stated, moreover, that the castle in Brunswick, Germany, which was very much injured by fire not long ago, is to be ornamented with this imitation-marble, as also the new music-hall in Hamburg. Besides these uses, very tasteful mosaic-work can be made from it. This is done by first sketching the figure or figures upon the stone; they are next neatly cut out with fine instru- men~s, and then, finally, filled in again with the same artiricial mass of the desired shades of color. The stir- face is then polished as though it were native marble, until it has taken on a perfect lustre, In so far as the name Hellenemstein is concerned, it may be remarked that the nature of the mass is such that one can imitate, even to the point of decep- tion, the most excellent and purest kinds of marble ob- tained from the Hellenic Mountains of Greece. Nor, as giving rise to quite a new branch of industry, does the imitation, in any respect, fall far behind those rare kinds of Grecian native marble. Slabs for building purposes, cornice-work, etc., are manufactured in large blocks. These are afterwards further wrought by means of steam power, under the circular saw and the planing machine; then, finally, they come into the hands of the worker, who finishes them in accordance with the purposes for which they are designed. Common Mortar. LIME is produced in almost every part of the civil- ized world by burning either limestone or shells. This burning process brings about the expulsion of carbonic acid in the state of gaslimestone and shells being nothing but a carbonate of lime, with some or- ganic impurities which are also driven off by the heat; and often small amounts of silica, alumina, and mag- nesia, which combine during the process of burning with a small portion of the lime. The resulting pro- ducts of the burning or calcining is commonly called quicklime, which is, in fact, the oxide of a metal called calcium. This quicklime has a very strong affinity for carbonic acid, and also for water. It will absorb them from the atmosphere when left exposed, and thus quickly deteriorate. The carbonic acid is much more injurious than the water. It deadens the lime, so to speak. When mixed with water so as to form a pasty mass, it may be kept for some time. When this pasty mass is still further mixed with sand, it forms ordinary mortar. Simple lime as a paste hardens as well as mortar, but it forms only a loose mass, of too weak a consistency to bind the stones of a wall together. A striking illus- tration of this is found in the ruins of Fort Putnum, situated on the top of a hill behind West-Point, on the Hudson River. The mortar there is all crumbling to dust, and the stones are falling apart, evidently because no sand, or an insufficient amount of it, was used in the preparation of the mortar, probably on account of the scarcity of it on the top of this granite rock. When the quantity of sand in mortar is sufficient, it hardens gradually in its place between the bricks until it is as solid and firm as the original limestone. It ad- heres very strongly to the bricks, and then cements them together. Pure lime paste without sand will only cement in very thin layers between two smooth stones. Where, however, the stones are irregular, they consequently offer many thick places in the layers of lime paste. It is necessary, therefore, that these places should be interspersed with points of attachment for the lime. These are found in sand, coarse gravel, and irregular small stones. Much sand in the mortar is good, public opinion to the contrary notwithstand- ing. In fact, as little lime as possible should be used; and, as a rule, only as much lime paste should be mixed with sand as will fill up the interstices of the sand; in other words, as much as the sand will take up without increasing its bulk. This is found to be ac- complished by using six pounds of sand for every one pound of lime; or, in bulk, three to four cubic feet of sand for every cubic foot of lime paste. Good. fat lime will stand more sand; poor sandy lime less, sometimes only two cubic foot for every one cubic foot of lime. The sand of course -must be pure. When it contains clay, more can be used, in order to make a consistent mortar, but it is always of inferior quality. Sand con- taining humus, bog-earth, peat, or other organic re- mains, is entirely unfit for mortar. Although mortar sets sufficiently in a few days or weeks to enable a wall to withstand pressure, yet the hardening process goes on so slowly that it attains its maximum degree of hardness only after years or even after many centuries of time have elapsed. In the last case, the wall becomes to all intents and pur- poses as solid as if made of one single piece of stone. The apparent superiority of mortar in olden times over that of the present day must be due solely to the long time it has had to harden, since it has been proved that no difference exists as regards the nature of the ingredients employed. When the French army, some seventy-five years ago, were guilty of the vandalism of destroying the beautifui castle of Heidell1~rg, in Ger- many, they placed gunpowder in an old square tower, built about the year 1100. The result was that the whole tower was displaced in one single piece. It now stands very much inclined, and shows the effects of the explosion only by one large crack, running from top to bottom. In a building of recent structure, where the effects of time would not have been suffi- ~ient to have hardened the mortar, scarcely one stotie would have remained attached to another when sub- mitted to such a severe trial. It is certain that many buildings erected at present will stand the test of time, and be inherited by posterity as models of solid masonry, just as those of the middle ages are now by us. The inferior ones will crumble and be unknown to them, just as the inferior ones of olden times have crumbled and are now unknown to us. This hardening of mortar in the course of ages is so difficult to explain, on chemical principles, that it is even denied by some, and asserted that, as soon as the lime has absorbed all the carbonic acid from the at- mosphere it is capable of, the hardening process is finished; and this, it is said, takes place in a single season. Experiments, however, have shown that the mortar in the interior parts of walls built three hun. dred years ago was still caustic, or, in other words, had not been changed into carbonate of lime, and that part of the lime had combined with the silica, and formed a silicate of lime. Experiments made for the purpose prove that, when quicklime is mixed with sand, the amount of silicate of lime which does not at first exist, and which is soluble in hydrochloric acid, increases continually in the course of time, and in one week amounts to one half per cent; in five weeks to one per cent; in ten months to seven pe~ cent. As, however, mortar will harden when, instead of si- licious limestone, sand is used, the hardening must be due also to other than mere chemical causes. One of the most important among these is probably the crys- tallization of the hydrate of lime, which takes place slowly under the influence of the periodically moist and dry states of the atmosphere. The hardening of mortar is therefore probably due to the three causes mentioned combined, namely, the absorption of carbon- ic acid, the slow combination of lime with the silex, the consequent increase of the amount of silicate of lime, and, lastly, the crystallization of the hydrate of lime. The absorption of carbonic acid induces a separation of an equivalent amount of water from the hydrate of lime, and is the cause of the moisture of newly-built walls. As one square yard of a coating of mortar one inch thick weighs nearly one hundred pounds and contains four pounds of lime, with which more than one pound of water is combined, in a room with a plastered surface of forty square yards, this will amount to some forty pounds. This will all be given out, and the process go on until the quick-lime has combined with the carbonic acid from the atmosphere. Sometimes, when the water thus given out dries quickly upon such newly-built walls, effiorescences are observed. They have been analyzed by VOGEL and KIJHLMAN in Germany, and found to consist of sulphate of soda, carbonate of soda, common salt, carbonate of potassa, and chloride of potassium. It is probable that some of these alkalies were taken up by the lime- stone from the ashes of the fuel used in burning the lime. New Paint for Floors. WE learn that a new kind of paint, especially good for floors, is made out of water-glass. It unites not only the qualities of beauty and durability, but is also advantageous as a means of protection against the ac- tion of fire. In order to lay on a covering of this paint, first of all the floor is neatly cleaned, then any cracks or crevices between the boards that may exist are luted with a thick dough made of water-glass and pal- verized chalk or gypsum. By means of a stiff brush a coating of water-glass of the consistency, say, of syrup. is then spread over the floor. Again in the same man- ner a second coating is laid on, consi sting of water- glass mixed with the desired color. It must, however be a mineral color, from the fact that the alkalies of the water-glass commonly decompose vegetable colors. This coating having become dry, other layers of water glass may be thereafter given, until the tioor has taken on the required lustrous appearance. In order to give the surface a brightness indicative of polish, it ~s ground off a little, oUed, am~ ~reu.ghly dried. In 13 The Manufacturer and Builder. this way a coating for, the floor is obtained which is very durable, since the water-glass is not worn away either by means of heat, or yet, on account of its hardness, by means of continued use. As regards beauty and utility, floors coated in this manner are found to be fully equal to the best lacquered or var- nished ones. Apatite: Its Importance in Domestic Economy. APATITE is a mineral phosphate of lime, similar in character to the bones of animals. This mineral plies- Phate is most essential to various kinds of vegetable growths, it being taken up from the earth and assimi- lated as one of their essential elements. The mineral part of the bones of animals consists to a great extent of phosphate of lime. It ipust there- fore naturally play an important part in a~riculture; and, indeed, such for ages has been the general impres- sion. Burnt bones lose by calcination one third part of their weight. This consists of organic matters which is destroyed by the process of combustion. The residue is phosphate of lime, with from ten to twelve per cent of carbonate of lime, and a little fluoride of calcium and magnesia. Apatite, on the other hand, contains ninety per cent of phosphate of lime. The residue is chloride and fluoride of calcium. In the Canadian apatite about five per cent of silica and a small portion of carbon have been found. Burnt bones are much employed in the manufacture of porcelain. They are mixed to the extent of nearly forty per cent with the other ingredients, such as clay, feldspar, and flint. The reason of its employment lies in the fact that the phosphoric acid contained in the compound is the vitrifiable element, which, at a high temperature, converts the other ingredieiits into a transparent enamel. Brazil and other countries, where the hides and bones of animals are of more account than their flesh, supplies the largest number of the latter for fer- tilizing purposes. Bones are likewise used in the arts fol the manufacture of buttons, combs, and also in the production of phosphoric acid, phosphorus, phosphate of soda, and microcosmic salt. A large amount of bones are utilized by exposure to continued steam, which extracts from them all their grease and other organic matter. They are then ground and cold to the husbandman. The supply of bones is altogether in- adequate to the demand, and in order to make up this deficiency other sources of phosphate of lime have been sought out. (inane, or Huamo, as it is termed in the language of the Peruvians, which consists of the accumulated and altered excretions of certain kinds of sea-fowls, was discovered in the hot climates of Africa and Peru some thirty years ago. It found a ready market in France and En gland. Coprolites were aho found in large deposits, they proving to be the exuvi~ of animals of former times, or, in other words, the fossil excrements of extinct animals. They contain about sixty per cent of phosphate of lime. The crys- talline mineral phosphate of lime, or apatite, is found in nature in large quantities, especially in Norway, Sweden, Spain, Canada, and also in other localities. It has, of late years, been eagerly sought after to sup- ply the great demand for phosphates as fertilizers. It is, however, well known that neither bones, cop- rolites, nor apatite is applied to the soil in its insoluble state, being, in that condition, comparatively useless as regards the nutrition of plants. In order to render them. fit for agricultural purposes, they must be con- verted into the soluble superphosphate. In order to effect this, one hundred pounds are treated with sixty- three pounds of oil of vitriol. The soluble superphos- phate of lime is obtained, which product is generally employed for fertilizing lands. The quantity of superphosphate of lime at the pre- sent day manufactured in England, the United States, France, and Germany, is said to be one thousand tons per day. This rate of production, at an average price of forty oollars ncr ton, would amount to the sum of fourteen mil- lions of dollars per ni num. It is now well known ti-at the guano supply is gradually diminishing. We make no don.bt that, with the increase of population and he extended cultivatiQa of baipen and worn-out soils, the demand for superpho~phate of lime will reach at least twenty millipas per annum. This shows the impor- tance of utilizing natures gifts to their fullest extent. The cp~sumption of superphosphate of lime, ifi place of other substances use,d in. the arts, is now comparatively small, but may, at no distant day, find a large applica- tion in the manufacture of phosphorus and phosphate of soda. A few years ago there was a good deal of in- quiry made for phosphate of soda for the use of dis- tillers, whose experiments proved that an addition of it would not alone accelerate the process of fermenta- tion, but also produce an increase in the yield. Upon being applied for, the material could not be obtained. Some fine crystals of phosphate of soda were obtained from Canadian apatite; nor is there any reason why phosphorus, not yet manufactured in this country, but imported from Germany and France to the value of one hundred thousand dollars per annum, should not be obtained in this country from the native mineral. In the manufacture of phosphorus this mineral apatite is frst converted into a superphosphate, then mixed with plenty of charcoal and volatilized at a.liigh heat. Phosphorus is the resulting product. It is used in the manufacture of friction matches, and also for the extermination of vermin. The phosphoric nodules from the lower siliirian rocks of Canada, and the coprohites found in the fossiliferous rocks, are all of organic origin, and contain phosphate of lime in various proportions rang-, ing from fifteen to eighty-five per cent. These nodules contain frequently fragments of small shells; such sometimes present a spiral or other form of interior structure derived from their animal organization. Cop- rohites were first noticed by BUCKLAND on the English coast, but are now. found ii~ many- oth r localities. They are used solely in the making of superphosphiate of lime; while apatite, containing a uniform percentage of phosphate of lime; bids fair to compete with the other substances already mentioned in the manufac- ture of the various chemical compounds. Gun-Cotton. So2rE twenty years ago, there was time same en- citement about gun-cotton as recently about nitro- glycerine. Prof. SOiIoENBErN is usually mentioned as it~ discoverer, though already, in 1833, BRAcONNOT found that when starch was heated in strong nitric acid until dissolved, and then poured into cold water a white substance was precipitated, which, after dry- ing, was highly combustible, and burned without leaving any smoke. PELoUsE found, in 1838, that paper, linen, cotton, and all ligneous fibres in general, when plunged first into strong nitric acid, then washed with water and dried, possessed the same property, without losing their original appearance. SciroEN- BEIN described first in detail the best manner of pro- ceeding to make cotton explosive, so that it could be used as a substitute for gunpowder. The chemical name given to this preparation is pyroxyline; the preparation of starch first made by B~mAcoNvoT lie called xyloidine. To make gun-cotton or pyroxyhine, clean cotton is entirely immersed, for the space of ten or fifteen minutes, in a mixture of stron0 nitric acid, and with one, two, or three parts of sulphuric acid. The acid is then pressed out, and the cotton washed with water until all the acid is removed. It is then quickly dried at a temperature below 212~ Falir. This is the dan- gerous part of the operation, as, during the drying, there is great danger of an explosion. Time precess of drying in stoves, at first used for this purpose, is therefore abolished, and the cotton is spread out and a free current of air allowed to pass over it, so as to keep it cool. It ignites and explodes violently at 35fi? Fahr. without leaving ash or smoke. This temperatum-e is so much below that required for gun- powder, that gun-cotton may be placed loosely upon gunpowder, and exploded by means of a hot wire without setting fire to the gunpowder. Gunpowder, in fact, burns not only, comparatively, speaking, very slow during its so-called explosion, but is also tar- dy in taking fire. This fact is beautifully illus- trated by the following wperiment. When a mix- ture of gunpowder and fine iron filings are thrown into a shallow dish containing burning alcohol, the iron will take fire and burn in the alcoholic flame, while the grains of gunpowder will fall through the flame with- out igniting, and be found at the bottom of the alcohol unburnt. A blow with a hammer upon an anvil will never ignite gunpowder; it will, however, explode gun-cotton. Chemists do not, as yet, perfectly agree as to the chemical formula for gun-cotton. One thing is certain, however, that after the change it contains nitrogen, which element does not exist in cotton. It also con- tains a greatly increased amount of oxygen. The change that common cotton undergoes when transformed into gun-cotton is very remarkable; it feels rougher than before, and is soluble in ether. This solution, diluted with alcohol, is called collodion, and is at present used as a very quickly drying var- nish, and is a most indispensable article in modern photography.. In fact, this is the chief use of gun- cotton at the present day, as it 1-as been found unfit and unsafe for gunnery, as well fer reason of the in- urious effects of its gases on the fire-arms, as for its too sudden combustion, acting like a fulminate and bursting the guns, and also occasionally exploding by percussion. It has been found to be about four times stronger than gunpowder, and has therefore been used effectually in combination with nitre, or, better still, chlorate of potassa, which increases its power con- siderably, but makes it still more unsafe in regard to explosion by percussion. Paper treated in this manner becomes quite as explosive, and when moistened with solutions of salts of strontia, of copper, or baryta, gives beautiful red, green, and white lights. In this, or a similar mannem pyrotechnists may make an extensive use of this dis covery. For mining and rock-blasting its use has been al- nest abandoned, and. now, where gunpowder is con- sidered insufficient, nitro-glycerine has taken the place of it. The Preservation of Wood by Immersion. THE processes for time preservation of wood may be divided into three groups, namely: processes by immer- sion; processes by pressure in closed vessels, (which are exclusively employed for dry wood,) and processes founded on the displacement of the sap (which are only employed for green wood.) In time present article we shall describe time methods by immersion. Attempts to impregnate wood by the method of im- mersion were the first experiments undertaken. As early as 1740, FAGOL, a Frenchman, tried to impregnate wood with alum, sulphate of iron, and various other substances, in solutions of which he immersed it for several days. In 1756, HALLEIm recommended vegeta- ble oil for the same purpose. In 1767, JAcxsoN indi- cated time use of a solution of sea salt, to which sulphate of iron and magnesia, alum, lime, and potassa were to be added. In 1779, PALLAS proposed to mineralize wood by dipping it first in a solution of green copperas and afterward in milk of lime. In 1830, KYAN, in England, tried to preserve wood by simply immersing it in a solution containing two per cent of bichierid s of mercury. Not long since, experiments ~ere made in France and Germany within a large number of rail- road ties, by keeping them several hours in a solution containing 1.5 per cent of sulphate of copper, at a tem- perature of 1 60~ Fahr. This preparation is, how- ever, altogether insufficient for the preservation of fir or pine wood, and in general for light woods which contain a large amount of nitrogenous substances; but it seems to increase considerably the durability of oak. The wood is timus surrounded by a very thmhm coat- ing, which is not liable to decay nor to time attacks of insects, and which retards time alteration of the inner parts. These are, however, not imnpregnated at all by 14

The Manufacturer and Builder. this way a coating for, the floor is obtained which is very durable, since the water-glass is not worn away either by means of heat, or yet, on account of its hardness, by means of continued use. As regards beauty and utility, floors coated in this manner are found to be fully equal to the best lacquered or var- nished ones. Apatite: Its Importance in Domestic Economy. APATITE is a mineral phosphate of lime, similar in character to the bones of animals. This mineral plies- Phate is most essential to various kinds of vegetable growths, it being taken up from the earth and assimi- lated as one of their essential elements. The mineral part of the bones of animals consists to a great extent of phosphate of lime. It ipust there- fore naturally play an important part in a~riculture; and, indeed, such for ages has been the general impres- sion. Burnt bones lose by calcination one third part of their weight. This consists of organic matters which is destroyed by the process of combustion. The residue is phosphate of lime, with from ten to twelve per cent of carbonate of lime, and a little fluoride of calcium and magnesia. Apatite, on the other hand, contains ninety per cent of phosphate of lime. The residue is chloride and fluoride of calcium. In the Canadian apatite about five per cent of silica and a small portion of carbon have been found. Burnt bones are much employed in the manufacture of porcelain. They are mixed to the extent of nearly forty per cent with the other ingredients, such as clay, feldspar, and flint. The reason of its employment lies in the fact that the phosphoric acid contained in the compound is the vitrifiable element, which, at a high temperature, converts the other ingredieiits into a transparent enamel. Brazil and other countries, where the hides and bones of animals are of more account than their flesh, supplies the largest number of the latter for fer- tilizing purposes. Bones are likewise used in the arts fol the manufacture of buttons, combs, and also in the production of phosphoric acid, phosphorus, phosphate of soda, and microcosmic salt. A large amount of bones are utilized by exposure to continued steam, which extracts from them all their grease and other organic matter. They are then ground and cold to the husbandman. The supply of bones is altogether in- adequate to the demand, and in order to make up this deficiency other sources of phosphate of lime have been sought out. (inane, or Huamo, as it is termed in the language of the Peruvians, which consists of the accumulated and altered excretions of certain kinds of sea-fowls, was discovered in the hot climates of Africa and Peru some thirty years ago. It found a ready market in France and En gland. Coprolites were aho found in large deposits, they proving to be the exuvi~ of animals of former times, or, in other words, the fossil excrements of extinct animals. They contain about sixty per cent of phosphate of lime. The crys- talline mineral phosphate of lime, or apatite, is found in nature in large quantities, especially in Norway, Sweden, Spain, Canada, and also in other localities. It has, of late years, been eagerly sought after to sup- ply the great demand for phosphates as fertilizers. It is, however, well known that neither bones, cop- rolites, nor apatite is applied to the soil in its insoluble state, being, in that condition, comparatively useless as regards the nutrition of plants. In order to render them. fit for agricultural purposes, they must be con- verted into the soluble superphosphate. In order to effect this, one hundred pounds are treated with sixty- three pounds of oil of vitriol. The soluble superphos- phate of lime is obtained, which product is generally employed for fertilizing lands. The quantity of superphosphate of lime at the pre- sent day manufactured in England, the United States, France, and Germany, is said to be one thousand tons per day. This rate of production, at an average price of forty oollars ncr ton, would amount to the sum of fourteen mil- lions of dollars per ni num. It is now well known ti-at the guano supply is gradually diminishing. We make no don.bt that, with the increase of population and he extended cultivatiQa of baipen and worn-out soils, the demand for superpho~phate of lime will reach at least twenty millipas per annum. This shows the impor- tance of utilizing natures gifts to their fullest extent. The cp~sumption of superphosphate of lime, ifi place of other substances use,d in. the arts, is now comparatively small, but may, at no distant day, find a large applica- tion in the manufacture of phosphorus and phosphate of soda. A few years ago there was a good deal of in- quiry made for phosphate of soda for the use of dis- tillers, whose experiments proved that an addition of it would not alone accelerate the process of fermenta- tion, but also produce an increase in the yield. Upon being applied for, the material could not be obtained. Some fine crystals of phosphate of soda were obtained from Canadian apatite; nor is there any reason why phosphorus, not yet manufactured in this country, but imported from Germany and France to the value of one hundred thousand dollars per annum, should not be obtained in this country from the native mineral. In the manufacture of phosphorus this mineral apatite is frst converted into a superphosphate, then mixed with plenty of charcoal and volatilized at a.liigh heat. Phosphorus is the resulting product. It is used in the manufacture of friction matches, and also for the extermination of vermin. The phosphoric nodules from the lower siliirian rocks of Canada, and the coprohites found in the fossiliferous rocks, are all of organic origin, and contain phosphate of lime in various proportions rang-, ing from fifteen to eighty-five per cent. These nodules contain frequently fragments of small shells; such sometimes present a spiral or other form of interior structure derived from their animal organization. Cop- rohites were first noticed by BUCKLAND on the English coast, but are now. found ii~ many- oth r localities. They are used solely in the making of superphosphiate of lime; while apatite, containing a uniform percentage of phosphate of lime; bids fair to compete with the other substances already mentioned in the manufac- ture of the various chemical compounds. Gun-Cotton. So2rE twenty years ago, there was time same en- citement about gun-cotton as recently about nitro- glycerine. Prof. SOiIoENBErN is usually mentioned as it~ discoverer, though already, in 1833, BRAcONNOT found that when starch was heated in strong nitric acid until dissolved, and then poured into cold water a white substance was precipitated, which, after dry- ing, was highly combustible, and burned without leaving any smoke. PELoUsE found, in 1838, that paper, linen, cotton, and all ligneous fibres in general, when plunged first into strong nitric acid, then washed with water and dried, possessed the same property, without losing their original appearance. SciroEN- BEIN described first in detail the best manner of pro- ceeding to make cotton explosive, so that it could be used as a substitute for gunpowder. The chemical name given to this preparation is pyroxyline; the preparation of starch first made by B~mAcoNvoT lie called xyloidine. To make gun-cotton or pyroxyhine, clean cotton is entirely immersed, for the space of ten or fifteen minutes, in a mixture of stron0 nitric acid, and with one, two, or three parts of sulphuric acid. The acid is then pressed out, and the cotton washed with water until all the acid is removed. It is then quickly dried at a temperature below 212~ Falir. This is the dan- gerous part of the operation, as, during the drying, there is great danger of an explosion. Time precess of drying in stoves, at first used for this purpose, is therefore abolished, and the cotton is spread out and a free current of air allowed to pass over it, so as to keep it cool. It ignites and explodes violently at 35fi? Fahr. without leaving ash or smoke. This temperatum-e is so much below that required for gun- powder, that gun-cotton may be placed loosely upon gunpowder, and exploded by means of a hot wire without setting fire to the gunpowder. Gunpowder, in fact, burns not only, comparatively, speaking, very slow during its so-called explosion, but is also tar- dy in taking fire. This fact is beautifully illus- trated by the following wperiment. When a mix- ture of gunpowder and fine iron filings are thrown into a shallow dish containing burning alcohol, the iron will take fire and burn in the alcoholic flame, while the grains of gunpowder will fall through the flame with- out igniting, and be found at the bottom of the alcohol unburnt. A blow with a hammer upon an anvil will never ignite gunpowder; it will, however, explode gun-cotton. Chemists do not, as yet, perfectly agree as to the chemical formula for gun-cotton. One thing is certain, however, that after the change it contains nitrogen, which element does not exist in cotton. It also con- tains a greatly increased amount of oxygen. The change that common cotton undergoes when transformed into gun-cotton is very remarkable; it feels rougher than before, and is soluble in ether. This solution, diluted with alcohol, is called collodion, and is at present used as a very quickly drying var- nish, and is a most indispensable article in modern photography.. In fact, this is the chief use of gun- cotton at the present day, as it 1-as been found unfit and unsafe for gunnery, as well fer reason of the in- urious effects of its gases on the fire-arms, as for its too sudden combustion, acting like a fulminate and bursting the guns, and also occasionally exploding by percussion. It has been found to be about four times stronger than gunpowder, and has therefore been used effectually in combination with nitre, or, better still, chlorate of potassa, which increases its power con- siderably, but makes it still more unsafe in regard to explosion by percussion. Paper treated in this manner becomes quite as explosive, and when moistened with solutions of salts of strontia, of copper, or baryta, gives beautiful red, green, and white lights. In this, or a similar mannem pyrotechnists may make an extensive use of this dis covery. For mining and rock-blasting its use has been al- nest abandoned, and. now, where gunpowder is con- sidered insufficient, nitro-glycerine has taken the place of it. The Preservation of Wood by Immersion. THE processes for time preservation of wood may be divided into three groups, namely: processes by immer- sion; processes by pressure in closed vessels, (which are exclusively employed for dry wood,) and processes founded on the displacement of the sap (which are only employed for green wood.) In time present article we shall describe time methods by immersion. Attempts to impregnate wood by the method of im- mersion were the first experiments undertaken. As early as 1740, FAGOL, a Frenchman, tried to impregnate wood with alum, sulphate of iron, and various other substances, in solutions of which he immersed it for several days. In 1756, HALLEIm recommended vegeta- ble oil for the same purpose. In 1767, JAcxsoN indi- cated time use of a solution of sea salt, to which sulphate of iron and magnesia, alum, lime, and potassa were to be added. In 1779, PALLAS proposed to mineralize wood by dipping it first in a solution of green copperas and afterward in milk of lime. In 1830, KYAN, in England, tried to preserve wood by simply immersing it in a solution containing two per cent of bichierid s of mercury. Not long since, experiments ~ere made in France and Germany within a large number of rail- road ties, by keeping them several hours in a solution containing 1.5 per cent of sulphate of copper, at a tem- perature of 1 60~ Fahr. This preparation is, how- ever, altogether insufficient for the preservation of fir or pine wood, and in general for light woods which contain a large amount of nitrogenous substances; but it seems to increase considerably the durability of oak. The wood is timus surrounded by a very thmhm coat- ing, which is not liable to decay nor to time attacks of insects, and which retards time alteration of the inner parts. These are, however, not imnpregnated at all by 14

The Manufacturer and Builder. this way a coating for, the floor is obtained which is very durable, since the water-glass is not worn away either by means of heat, or yet, on account of its hardness, by means of continued use. As regards beauty and utility, floors coated in this manner are found to be fully equal to the best lacquered or var- nished ones. Apatite: Its Importance in Domestic Economy. APATITE is a mineral phosphate of lime, similar in character to the bones of animals. This mineral plies- Phate is most essential to various kinds of vegetable growths, it being taken up from the earth and assimi- lated as one of their essential elements. The mineral part of the bones of animals consists to a great extent of phosphate of lime. It ipust there- fore naturally play an important part in a~riculture; and, indeed, such for ages has been the general impres- sion. Burnt bones lose by calcination one third part of their weight. This consists of organic matters which is destroyed by the process of combustion. The residue is phosphate of lime, with from ten to twelve per cent of carbonate of lime, and a little fluoride of calcium and magnesia. Apatite, on the other hand, contains ninety per cent of phosphate of lime. The residue is chloride and fluoride of calcium. In the Canadian apatite about five per cent of silica and a small portion of carbon have been found. Burnt bones are much employed in the manufacture of porcelain. They are mixed to the extent of nearly forty per cent with the other ingredients, such as clay, feldspar, and flint. The reason of its employment lies in the fact that the phosphoric acid contained in the compound is the vitrifiable element, which, at a high temperature, converts the other ingredieiits into a transparent enamel. Brazil and other countries, where the hides and bones of animals are of more account than their flesh, supplies the largest number of the latter for fer- tilizing purposes. Bones are likewise used in the arts fol the manufacture of buttons, combs, and also in the production of phosphoric acid, phosphorus, phosphate of soda, and microcosmic salt. A large amount of bones are utilized by exposure to continued steam, which extracts from them all their grease and other organic matter. They are then ground and cold to the husbandman. The supply of bones is altogether in- adequate to the demand, and in order to make up this deficiency other sources of phosphate of lime have been sought out. (inane, or Huamo, as it is termed in the language of the Peruvians, which consists of the accumulated and altered excretions of certain kinds of sea-fowls, was discovered in the hot climates of Africa and Peru some thirty years ago. It found a ready market in France and En gland. Coprolites were aho found in large deposits, they proving to be the exuvi~ of animals of former times, or, in other words, the fossil excrements of extinct animals. They contain about sixty per cent of phosphate of lime. The crys- talline mineral phosphate of lime, or apatite, is found in nature in large quantities, especially in Norway, Sweden, Spain, Canada, and also in other localities. It has, of late years, been eagerly sought after to sup- ply the great demand for phosphates as fertilizers. It is, however, well known that neither bones, cop- rolites, nor apatite is applied to the soil in its insoluble state, being, in that condition, comparatively useless as regards the nutrition of plants. In order to render them. fit for agricultural purposes, they must be con- verted into the soluble superphosphate. In order to effect this, one hundred pounds are treated with sixty- three pounds of oil of vitriol. The soluble superphos- phate of lime is obtained, which product is generally employed for fertilizing lands. The quantity of superphosphate of lime at the pre- sent day manufactured in England, the United States, France, and Germany, is said to be one thousand tons per day. This rate of production, at an average price of forty oollars ncr ton, would amount to the sum of fourteen mil- lions of dollars per ni num. It is now well known ti-at the guano supply is gradually diminishing. We make no don.bt that, with the increase of population and he extended cultivatiQa of baipen and worn-out soils, the demand for superpho~phate of lime will reach at least twenty millipas per annum. This shows the impor- tance of utilizing natures gifts to their fullest extent. The cp~sumption of superphosphate of lime, ifi place of other substances use,d in. the arts, is now comparatively small, but may, at no distant day, find a large applica- tion in the manufacture of phosphorus and phosphate of soda. A few years ago there was a good deal of in- quiry made for phosphate of soda for the use of dis- tillers, whose experiments proved that an addition of it would not alone accelerate the process of fermenta- tion, but also produce an increase in the yield. Upon being applied for, the material could not be obtained. Some fine crystals of phosphate of soda were obtained from Canadian apatite; nor is there any reason why phosphorus, not yet manufactured in this country, but imported from Germany and France to the value of one hundred thousand dollars per annum, should not be obtained in this country from the native mineral. In the manufacture of phosphorus this mineral apatite is frst converted into a superphosphate, then mixed with plenty of charcoal and volatilized at a.liigh heat. Phosphorus is the resulting product. It is used in the manufacture of friction matches, and also for the extermination of vermin. The phosphoric nodules from the lower siliirian rocks of Canada, and the coprohites found in the fossiliferous rocks, are all of organic origin, and contain phosphate of lime in various proportions rang-, ing from fifteen to eighty-five per cent. These nodules contain frequently fragments of small shells; such sometimes present a spiral or other form of interior structure derived from their animal organization. Cop- rohites were first noticed by BUCKLAND on the English coast, but are now. found ii~ many- oth r localities. They are used solely in the making of superphosphiate of lime; while apatite, containing a uniform percentage of phosphate of lime; bids fair to compete with the other substances already mentioned in the manufac- ture of the various chemical compounds. Gun-Cotton. So2rE twenty years ago, there was time same en- citement about gun-cotton as recently about nitro- glycerine. Prof. SOiIoENBErN is usually mentioned as it~ discoverer, though already, in 1833, BRAcONNOT found that when starch was heated in strong nitric acid until dissolved, and then poured into cold water a white substance was precipitated, which, after dry- ing, was highly combustible, and burned without leaving any smoke. PELoUsE found, in 1838, that paper, linen, cotton, and all ligneous fibres in general, when plunged first into strong nitric acid, then washed with water and dried, possessed the same property, without losing their original appearance. SciroEN- BEIN described first in detail the best manner of pro- ceeding to make cotton explosive, so that it could be used as a substitute for gunpowder. The chemical name given to this preparation is pyroxyline; the preparation of starch first made by B~mAcoNvoT lie called xyloidine. To make gun-cotton or pyroxyhine, clean cotton is entirely immersed, for the space of ten or fifteen minutes, in a mixture of stron0 nitric acid, and with one, two, or three parts of sulphuric acid. The acid is then pressed out, and the cotton washed with water until all the acid is removed. It is then quickly dried at a temperature below 212~ Falir. This is the dan- gerous part of the operation, as, during the drying, there is great danger of an explosion. Time precess of drying in stoves, at first used for this purpose, is therefore abolished, and the cotton is spread out and a free current of air allowed to pass over it, so as to keep it cool. It ignites and explodes violently at 35fi? Fahr. without leaving ash or smoke. This temperatum-e is so much below that required for gun- powder, that gun-cotton may be placed loosely upon gunpowder, and exploded by means of a hot wire without setting fire to the gunpowder. Gunpowder, in fact, burns not only, comparatively, speaking, very slow during its so-called explosion, but is also tar- dy in taking fire. This fact is beautifully illus- trated by the following wperiment. When a mix- ture of gunpowder and fine iron filings are thrown into a shallow dish containing burning alcohol, the iron will take fire and burn in the alcoholic flame, while the grains of gunpowder will fall through the flame with- out igniting, and be found at the bottom of the alcohol unburnt. A blow with a hammer upon an anvil will never ignite gunpowder; it will, however, explode gun-cotton. Chemists do not, as yet, perfectly agree as to the chemical formula for gun-cotton. One thing is certain, however, that after the change it contains nitrogen, which element does not exist in cotton. It also con- tains a greatly increased amount of oxygen. The change that common cotton undergoes when transformed into gun-cotton is very remarkable; it feels rougher than before, and is soluble in ether. This solution, diluted with alcohol, is called collodion, and is at present used as a very quickly drying var- nish, and is a most indispensable article in modern photography.. In fact, this is the chief use of gun- cotton at the present day, as it 1-as been found unfit and unsafe for gunnery, as well fer reason of the in- urious effects of its gases on the fire-arms, as for its too sudden combustion, acting like a fulminate and bursting the guns, and also occasionally exploding by percussion. It has been found to be about four times stronger than gunpowder, and has therefore been used effectually in combination with nitre, or, better still, chlorate of potassa, which increases its power con- siderably, but makes it still more unsafe in regard to explosion by percussion. Paper treated in this manner becomes quite as explosive, and when moistened with solutions of salts of strontia, of copper, or baryta, gives beautiful red, green, and white lights. In this, or a similar mannem pyrotechnists may make an extensive use of this dis covery. For mining and rock-blasting its use has been al- nest abandoned, and. now, where gunpowder is con- sidered insufficient, nitro-glycerine has taken the place of it. The Preservation of Wood by Immersion. THE processes for time preservation of wood may be divided into three groups, namely: processes by immer- sion; processes by pressure in closed vessels, (which are exclusively employed for dry wood,) and processes founded on the displacement of the sap (which are only employed for green wood.) In time present article we shall describe time methods by immersion. Attempts to impregnate wood by the method of im- mersion were the first experiments undertaken. As early as 1740, FAGOL, a Frenchman, tried to impregnate wood with alum, sulphate of iron, and various other substances, in solutions of which he immersed it for several days. In 1756, HALLEIm recommended vegeta- ble oil for the same purpose. In 1767, JAcxsoN indi- cated time use of a solution of sea salt, to which sulphate of iron and magnesia, alum, lime, and potassa were to be added. In 1779, PALLAS proposed to mineralize wood by dipping it first in a solution of green copperas and afterward in milk of lime. In 1830, KYAN, in England, tried to preserve wood by simply immersing it in a solution containing two per cent of bichierid s of mercury. Not long since, experiments ~ere made in France and Germany within a large number of rail- road ties, by keeping them several hours in a solution containing 1.5 per cent of sulphate of copper, at a tem- perature of 1 60~ Fahr. This preparation is, how- ever, altogether insufficient for the preservation of fir or pine wood, and in general for light woods which contain a large amount of nitrogenous substances; but it seems to increase considerably the durability of oak. The wood is timus surrounded by a very thmhm coat- ing, which is not liable to decay nor to time attacks of insects, and which retards time alteration of the inner parts. These are, however, not imnpregnated at all by 14

The Manufacturer and Builder. this way a coating for, the floor is obtained which is very durable, since the water-glass is not worn away either by means of heat, or yet, on account of its hardness, by means of continued use. As regards beauty and utility, floors coated in this manner are found to be fully equal to the best lacquered or var- nished ones. Apatite: Its Importance in Domestic Economy. APATITE is a mineral phosphate of lime, similar in character to the bones of animals. This mineral plies- Phate is most essential to various kinds of vegetable growths, it being taken up from the earth and assimi- lated as one of their essential elements. The mineral part of the bones of animals consists to a great extent of phosphate of lime. It ipust there- fore naturally play an important part in a~riculture; and, indeed, such for ages has been the general impres- sion. Burnt bones lose by calcination one third part of their weight. This consists of organic matters which is destroyed by the process of combustion. The residue is phosphate of lime, with from ten to twelve per cent of carbonate of lime, and a little fluoride of calcium and magnesia. Apatite, on the other hand, contains ninety per cent of phosphate of lime. The residue is chloride and fluoride of calcium. In the Canadian apatite about five per cent of silica and a small portion of carbon have been found. Burnt bones are much employed in the manufacture of porcelain. They are mixed to the extent of nearly forty per cent with the other ingredients, such as clay, feldspar, and flint. The reason of its employment lies in the fact that the phosphoric acid contained in the compound is the vitrifiable element, which, at a high temperature, converts the other ingredieiits into a transparent enamel. Brazil and other countries, where the hides and bones of animals are of more account than their flesh, supplies the largest number of the latter for fer- tilizing purposes. Bones are likewise used in the arts fol the manufacture of buttons, combs, and also in the production of phosphoric acid, phosphorus, phosphate of soda, and microcosmic salt. A large amount of bones are utilized by exposure to continued steam, which extracts from them all their grease and other organic matter. They are then ground and cold to the husbandman. The supply of bones is altogether in- adequate to the demand, and in order to make up this deficiency other sources of phosphate of lime have been sought out. (inane, or Huamo, as it is termed in the language of the Peruvians, which consists of the accumulated and altered excretions of certain kinds of sea-fowls, was discovered in the hot climates of Africa and Peru some thirty years ago. It found a ready market in France and En gland. Coprolites were aho found in large deposits, they proving to be the exuvi~ of animals of former times, or, in other words, the fossil excrements of extinct animals. They contain about sixty per cent of phosphate of lime. The crys- talline mineral phosphate of lime, or apatite, is found in nature in large quantities, especially in Norway, Sweden, Spain, Canada, and also in other localities. It has, of late years, been eagerly sought after to sup- ply the great demand for phosphates as fertilizers. It is, however, well known that neither bones, cop- rolites, nor apatite is applied to the soil in its insoluble state, being, in that condition, comparatively useless as regards the nutrition of plants. In order to render them. fit for agricultural purposes, they must be con- verted into the soluble superphosphate. In order to effect this, one hundred pounds are treated with sixty- three pounds of oil of vitriol. The soluble superphos- phate of lime is obtained, which product is generally employed for fertilizing lands. The quantity of superphosphate of lime at the pre- sent day manufactured in England, the United States, France, and Germany, is said to be one thousand tons per day. This rate of production, at an average price of forty oollars ncr ton, would amount to the sum of fourteen mil- lions of dollars per ni num. It is now well known ti-at the guano supply is gradually diminishing. We make no don.bt that, with the increase of population and he extended cultivatiQa of baipen and worn-out soils, the demand for superpho~phate of lime will reach at least twenty millipas per annum. This shows the impor- tance of utilizing natures gifts to their fullest extent. The cp~sumption of superphosphate of lime, ifi place of other substances use,d in. the arts, is now comparatively small, but may, at no distant day, find a large applica- tion in the manufacture of phosphorus and phosphate of soda. A few years ago there was a good deal of in- quiry made for phosphate of soda for the use of dis- tillers, whose experiments proved that an addition of it would not alone accelerate the process of fermenta- tion, but also produce an increase in the yield. Upon being applied for, the material could not be obtained. Some fine crystals of phosphate of soda were obtained from Canadian apatite; nor is there any reason why phosphorus, not yet manufactured in this country, but imported from Germany and France to the value of one hundred thousand dollars per annum, should not be obtained in this country from the native mineral. In the manufacture of phosphorus this mineral apatite is frst converted into a superphosphate, then mixed with plenty of charcoal and volatilized at a.liigh heat. Phosphorus is the resulting product. It is used in the manufacture of friction matches, and also for the extermination of vermin. The phosphoric nodules from the lower siliirian rocks of Canada, and the coprohites found in the fossiliferous rocks, are all of organic origin, and contain phosphate of lime in various proportions rang-, ing from fifteen to eighty-five per cent. These nodules contain frequently fragments of small shells; such sometimes present a spiral or other form of interior structure derived from their animal organization. Cop- rohites were first noticed by BUCKLAND on the English coast, but are now. found ii~ many- oth r localities. They are used solely in the making of superphosphiate of lime; while apatite, containing a uniform percentage of phosphate of lime; bids fair to compete with the other substances already mentioned in the manufac- ture of the various chemical compounds. Gun-Cotton. So2rE twenty years ago, there was time same en- citement about gun-cotton as recently about nitro- glycerine. Prof. SOiIoENBErN is usually mentioned as it~ discoverer, though already, in 1833, BRAcONNOT found that when starch was heated in strong nitric acid until dissolved, and then poured into cold water a white substance was precipitated, which, after dry- ing, was highly combustible, and burned without leaving any smoke. PELoUsE found, in 1838, that paper, linen, cotton, and all ligneous fibres in general, when plunged first into strong nitric acid, then washed with water and dried, possessed the same property, without losing their original appearance. SciroEN- BEIN described first in detail the best manner of pro- ceeding to make cotton explosive, so that it could be used as a substitute for gunpowder. The chemical name given to this preparation is pyroxyline; the preparation of starch first made by B~mAcoNvoT lie called xyloidine. To make gun-cotton or pyroxyhine, clean cotton is entirely immersed, for the space of ten or fifteen minutes, in a mixture of stron0 nitric acid, and with one, two, or three parts of sulphuric acid. The acid is then pressed out, and the cotton washed with water until all the acid is removed. It is then quickly dried at a temperature below 212~ Falir. This is the dan- gerous part of the operation, as, during the drying, there is great danger of an explosion. Time precess of drying in stoves, at first used for this purpose, is therefore abolished, and the cotton is spread out and a free current of air allowed to pass over it, so as to keep it cool. It ignites and explodes violently at 35fi? Fahr. without leaving ash or smoke. This temperatum-e is so much below that required for gun- powder, that gun-cotton may be placed loosely upon gunpowder, and exploded by means of a hot wire without setting fire to the gunpowder. Gunpowder, in fact, burns not only, comparatively, speaking, very slow during its so-called explosion, but is also tar- dy in taking fire. This fact is beautifully illus- trated by the following wperiment. When a mix- ture of gunpowder and fine iron filings are thrown into a shallow dish containing burning alcohol, the iron will take fire and burn in the alcoholic flame, while the grains of gunpowder will fall through the flame with- out igniting, and be found at the bottom of the alcohol unburnt. A blow with a hammer upon an anvil will never ignite gunpowder; it will, however, explode gun-cotton. Chemists do not, as yet, perfectly agree as to the chemical formula for gun-cotton. One thing is certain, however, that after the change it contains nitrogen, which element does not exist in cotton. It also con- tains a greatly increased amount of oxygen. The change that common cotton undergoes when transformed into gun-cotton is very remarkable; it feels rougher than before, and is soluble in ether. This solution, diluted with alcohol, is called collodion, and is at present used as a very quickly drying var- nish, and is a most indispensable article in modern photography.. In fact, this is the chief use of gun- cotton at the present day, as it 1-as been found unfit and unsafe for gunnery, as well fer reason of the in- urious effects of its gases on the fire-arms, as for its too sudden combustion, acting like a fulminate and bursting the guns, and also occasionally exploding by percussion. It has been found to be about four times stronger than gunpowder, and has therefore been used effectually in combination with nitre, or, better still, chlorate of potassa, which increases its power con- siderably, but makes it still more unsafe in regard to explosion by percussion. Paper treated in this manner becomes quite as explosive, and when moistened with solutions of salts of strontia, of copper, or baryta, gives beautiful red, green, and white lights. In this, or a similar mannem pyrotechnists may make an extensive use of this dis covery. For mining and rock-blasting its use has been al- nest abandoned, and. now, where gunpowder is con- sidered insufficient, nitro-glycerine has taken the place of it. The Preservation of Wood by Immersion. THE processes for time preservation of wood may be divided into three groups, namely: processes by immer- sion; processes by pressure in closed vessels, (which are exclusively employed for dry wood,) and processes founded on the displacement of the sap (which are only employed for green wood.) In time present article we shall describe time methods by immersion. Attempts to impregnate wood by the method of im- mersion were the first experiments undertaken. As early as 1740, FAGOL, a Frenchman, tried to impregnate wood with alum, sulphate of iron, and various other substances, in solutions of which he immersed it for several days. In 1756, HALLEIm recommended vegeta- ble oil for the same purpose. In 1767, JAcxsoN indi- cated time use of a solution of sea salt, to which sulphate of iron and magnesia, alum, lime, and potassa were to be added. In 1779, PALLAS proposed to mineralize wood by dipping it first in a solution of green copperas and afterward in milk of lime. In 1830, KYAN, in England, tried to preserve wood by simply immersing it in a solution containing two per cent of bichierid s of mercury. Not long since, experiments ~ere made in France and Germany within a large number of rail- road ties, by keeping them several hours in a solution containing 1.5 per cent of sulphate of copper, at a tem- perature of 1 60~ Fahr. This preparation is, how- ever, altogether insufficient for the preservation of fir or pine wood, and in general for light woods which contain a large amount of nitrogenous substances; but it seems to increase considerably the durability of oak. The wood is timus surrounded by a very thmhm coat- ing, which is not liable to decay nor to time attacks of insects, and which retards time alteration of the inner parts. These are, however, not imnpregnated at all by 14 The Manufacturer and Builder. the antiseptic liquid.; they preserve their germs of putrefaction, which develop the easier the mere the injected surface is removed, whether by friction, blows, or the driving in of nails. The decay commences then at the denudea points, and propagates itself to- ward the ceuttal parts. Baron CIIAMPv also indicated a method for preserv- ing weed, by dipping it when green into suet of 200~ Fahr. The water and the gases which are in- closed in the vegetable tissue escape, and by the con- densation which fellows upon cooling, a vacuum is produced, into which, by the pressure of the atmo- sphere, the suet is made to penetrate. Mr. PAvER made use of this experience, substituting for the suet, resin, heated to 30O~ Fahr., and in this manner intro- duced into a small poplar-tree three fifths of its weight of resin. Ventilation and Heating by Currents~ ThERE is a great deal of valuable information em- balmed in public documents which is not made as use- ful to the public as it might be if professional men would take the pains to put it into popular form. We shall take occasion, from time to time, to extract from official publications (and we hope, through the cour- tesy of the different departments, from unpublished sources also) such matter as we think may be interest- ing to our readers. Perhaps no subject has been more fully treated in such documents than that which stands at the head of this article; and we have con- densed from various reports some important state- ments concerning the apparatus employed for heating the Capitol at Washington. This apparatus was con- structed under the direction of Captain M. C. MEIGS, United States Engineer, now Brevet Major-General and Quart ermaster-Geneial U. S. A., with tbe assist- ance of Messrs. NASoN & DODGE, of New-York, and Mr. ROBERT BRIGGS. In 1860, the Senate ordered the publication of the papers relating to this matter, and the result was an extended report, from which, and from the report of Captain MEtGS to the Secretary of War, the following information has been obtained: NOTES ON STEAM HEATING IN VARIOUS EDIFICES. Utica Insane Asylzemn.For each 50 cubic feet of space within the inner surface of outer walls of build- in~, there is provided one square foot of surface of pipe heated by steam. The pipes,being one-inch pipes, have an outer surface of ~ of 1 square foot to each lineal foot of pipe, so that 1 square foot is given by 3 lineal feet of this one-inch pipe. Tills has proved more than needed. Stone walls at first plastered on walls recently furred. Like most lunatic asylums, central corridor with rooms on each side. in iifassaclcesetts, several asylums have 1 square foot to 75 cubic feet. Not found sufficient. Li Philadelphia, Dr. Kirkbrides insane asylum, 1 to 95, and found during this most severe winter to be enough. At Raleigh, I in 100; not yet tiled. Nadhville, Tennessee, 1 in 110; not tried. Boston 6ustoin-Ilouse, which has exceedingly heavy and thick walls of granite, has 2500 square feet of s--inch pipe, equal to 1,000 lineal feet. Space warmed not known, but result good. Insane Asylum, Kalamazoo, Michi- gan, 1 to 60. Jn Northampton, new asylum, 1 to 60. recommended. Patent Office, Washington, west wing, hot water, Has reservoir; safety-valve separating cistern; can make steam and blow it offi Works in cold weather above 2i2~, at a pressure of 4i- poundssay 2200; 1 square foot to 118 cubic feet, 945,000 cubic feet within walls. This winter the upper story has been unfin- ished, and has been kept warm efrough to exclude frost, and to permit plastering to be done. The whole upPer story is in one room, 208 x 29 high. Patent Office, west wing, used about one ton of coal a day in coldest weather. The lower stories have tlmick walls and arches; the upper has a ceiling plastered, fastened to an iron truss roof. Twelve coils in basement rooms, two furnaces. Pipe furnace. Presidents house, Washington.512,000 cubic feet, 1 to 100, hot water in basement, works above 2120, twelve coils. Air brought to coils by wooden trunk suspended in corridor arch of basement. Extreme consumption, one ton a day. Patent Office furnaces muuch the better. Both are pipe furnaces. South Wing, Capitol . tensionThe Representa- tives Hall is provided for separately by a special fan and system of pipes and ventilation. Contents, 139 x 93 x 30=405,372 cubic feet. Provided 100,000 cubic feet of air per minute for summer ventilation, and 50,000 feet per minute to be warmed in winter. Pipe, 50,000 lineal feet, or 10,006 square feet of heating surface, or 1 in 28 cubic feet of space. This is in very great ex- cess, but it is considered better to incur tile expense of a few feet muore pipe timan might be really needed for warming in order to be able to command always a powerful ventilation, even in the coldest weather, with- out chilling the atmuosphere of the roomu. Much of this air will escape into the surrounding corridors of principal and attic stories, with which numerous doors connect the hall. Hence, less provision is needed for warming these corridors Ihan would otilerwise be ne- cessary. Visiting each room in the building, and esti- mating the proportion of pipe that should be used in each room to tile cubic contents of the room, we find tile proportion to vary between tile extremes of 1 to SO and 1 to 110 cubic feet, tile average of the whole being about 1 to 100. It is assumued that one lineal foot of pipe will raise one cubic foot of air froiu 0 to 1000, and 0.875 cubic feet of air from 0 to 1400. Tile average difference of temperature in the first case being between 590 and 2120, and in tile second case, between 700 and 2120. The total quantity of pipe for the whole building, (soutil wing,) exclusive of the hall, is 20,500 lineal feet=5533 square feet of surface. We have, then, 23,170 feet of air to be warmed per minute for winter heating. In summer, we assume that double this quantity of air will be used for ventilation; or rather, that we shall provide the power to give this if it is wanted. To ileat one cubic foot of air at 00 Fahr. with con- stant rise of one atmosphere one degree, requires 0.02 units of heat. In the Hall of Representatives, 50,000 cubic feet of air per minute, raised fromu 00 to 1000, re- quire 100,000 units of heat, equivalent to about 86.7 pounds of water evaporated, or at the rate of 7.5 of water to one of coal, 11.5 pounds of coal per minute, 090 pounds per hour, 7.33 tons in twenty-four hours. In the corridors and commuittee-rooms, 20,000 cubic feet of air raised from 00 to 1400 require 50,000 units of heat, equivalent to 48.7 pounds of water evaporated, requiring 0.5 pounds of coal per minute or 390 pounds per hour. Total for hall, committee-rooms, and corri- dors, 1080 pounds of coal per hour, or 13.4 tons per twenty-four hours. This quantity of coal xviii be burned at the rate of nine pounds per hour upon each square foot of grate, and requires therefore 120 square feet of grate surface. Dividing timis among four boil- ers, we have for each grate 30 square feet of surface, or5feet x 0 feet. The temperature called for by the officers of the House, as most comfortable for the members, is seventy degrees, and this temperature is kept up throughout the whole room. The greatest variation as shown by thermometers placed in many different parts of the hall, both near the floor occupied by the members and against the xvall above the galleries, is only three de- grees Fahrenheit. By direction of tile officers of the Senate, the Senate Chamber is kept at a temperature two or three degrees lower, and the same uniformity of temperature is attained in the various parts of timis hall. In heating and ventilating the north wing, during the twelve months preceding the 1st of October, 1859, 088 tons of anthracite coal xvere consumed. In the south wing, duri