3 0 to 1 12 0 to 16 0 to 20 Times its weight of lead. of glass; covering the whole with common salt, and melting it in a smith's forge, in a covered crucible; he then opened the crucible, put a nail into it, and continued to do so till the iron was no longer attacked. The lead was thus precipitated which contained the gold, and was afterwards separated by cupellation. Humid Assay of Gold mixed with Iron Pyrites. Dissolve the ore in 12 times its weight of diluted nitric acid, gradually added; place it in a proper degree of heat; this takes up the soluble parts, and leaves the gold untouched, with the insoluble matrix, from which it may be separated by aqua regia. The gold may be again separated from the aqua regia by pouring ether upon it; the ether takes up the gold, and by being burnt off leaves The solution may contain it in its metallic state. iron, copper, manganese, calcareous earth, or argil; if it be evaporated to dryness, and the residuum heated to redness for an hour, ammonia will extract the copper; fuming nitric acid the earths; the acetic acid the manganese; and the muriatic acid the oxide of iron. The sulphur floats on the first solution, from which it should be separated by filtration. 1 12 to 0 18 The cupel must be heated red-hot for half an hour before any metal is put upon them, by which all moisture is expelled. When the cupel is almost white by heat the lead is put into it, and the fire increased till the lead becomes red-hot, smoking, and agitated by a motion of all its parts, called its circulation. Then the silver is to be put on the cupel, and the fire continued till the silver has entered the lead; and when the mass circulates well, the heat must be diminished by closing more or less the door of the assay furnace. The heat should be so regulated, that the metal on its surface may appear convex and ardent, while the cupel is less red; that the smoke shall rise to the roof of the muffle; that undulations shall be made in all directions; and that the middle of the metal shall appear smooth, with a small circle of litharge, which is continually imbibed by the cupel. By this treatment the lead and alloy will be entirely absorbed by the cupel, and the silver become By this process gold and silver are separated bright and shining, when it is said to lighten; from each other. These two metals equally reafter which, if the operation has been well persisting the action of fire and lead, must therefore formed, the silver will be covered with rainbow colors, which quickly undulate and cross each other, and then the button becomes fixed and solid. The diminution of weight shows the quantity of alloy. As all lead contains a small portion of silver, an equal weight with that used in the assay is tested off, and the product deducted from the assay-weight. This portion is called the witness. -Richardson's Metallic Arts. By Specific Gravity. The approximate weight of silver or gold in a nugget may be determined by calculation from its specific gravity. See MISCELLANEOUS. PARTING. be separated by other means. This is effected by different menstrua. Nitric acid, muriatic acid, and sulphur, which cannot attack gold, operate upon silver; and these are the principal agents employed in this process. Parting by nitric acid is most convenient, consequently most used; indeed, it is the only cae employed by goldsmiths. This is called simply parting. That made by the muriatic acid is by cementation, and is called cemented parting; and parting by sulphur is made by fusion, and called dry parting. Parting by Aqua-fortis. Ores and Earths Containing Gold. This process cannot succeed unless we attend to That which is now most generally used is by some essential circumstances: 1st. The gold and amalgamation. The proper quantity is taken and silver must be in a proper proportion, viz. the silver reduced to a powder; about one-tenth of its weight ought to be three parts to one of gold; though a of pure quicksilver is added, and the whole tritu- mass containing two parts of silver to one of gold rated in an iron mortar. The attraction subsisting may be parted. To judge of the quality of the between the gold and quicksilver, quickly unites metal to be parted, assayers make a comparison them in the form of an amalgam, which is pressed upon a touch-stone, between it and certain needles through shamoy leather; the gold is easily sepa-composed of gold and silver, in graduated propor rated from this amalgam, by exposure to a proper degree of heat, which evaporates the quicksilver, and leaves the gold. This evaporation should be made with luted vessels. This is the foundation of all the operations by which gold is obtained from the rich mines of Peru, in South America. Another Method. Take a quantity of the gold-sand and heat it red-hot; quench it in water; repeat this two or three times, and the color of the sand will become a reddish brown. Then mix it with twice its weight of litharge, and revive the litharge into lead, by adding a small portion of charcoal-dust, and exposing it to a proper degree of heat; when the lead revives, it separates the gold from the sand; and the freeing of the gold from the lead must be afterwards performed by cupellation. Another.-Bergmann assayed metallic ores containing gold, by mixing 2 parts of the ore, well pounded and washed, with 1 of litharge, and 3 tions, and properly marked; which are called proof needles. If this trial shows that the silver is not to the gold as three to one, the mass is improper for the operation, unless more silver be added. And 2dly, that the parting may be exact, the aqua-fortis must be very pure, especially free from any mixture of the sulphuric or muriatic acid. For if this were not attended to, a quantity of silver proportional to these two foreign acids would be separated during the solution; and this quantity of silver would remain mingled with the gold, which consequently would not be entirely purified by the operation. The gold and silver to be parted ought previously to be granulated by melting it in a crucible, and pouring it into a vessel of water, giving the water at the same time a rapid circular motion, by quickly stirring it round with a stick. The vessels generally used in this operation are called parting glasses, which ought to be very well annealed, and chosen free from flaws; as one of the chief inconveniences attending the operation is, that the glasses are apt to crack by exposure to cold, or even when touched by the hand. Some operators secure the bottom of the glasses by a coating composed of a mixture of new-slaked lime, with beer and whites of eggs, spread on a cloth, and wrapped round the glasses at the bottom; over which they apply a composition of clay and hair. The parting glasses should be placed in vessels containing water supported by trivets, with a fire under them; because if a glass should break, the contents are caught in the vessel of water. If the heat communicated to the water be too great, it may be properly regulated by pouring cold water gradually and carefully down the side of the vessel into a parting glass 15 inches high, and 10 or 12 inches wide at the bottom; placed in a copper pan 12 inches wide at bottom, 15 inches wide at top, and 10 inches high, there is usually put about 80 oz. of metal, with twice as much of aqua-fortis. The The nitric acid ought to be of 22° B., afterwards of 32° B. Little heat should be applied at first, as the liquor is apt to swell and rise over the vessel; but when the acid is nearly saturated, the heat may safely be increased. When the solution ceases, which is known by the effervescence discontinuing, the liquor is to be poured off; if any grains appear entire, more aqua-fortis must be added, till the silver is all dissolved. If the operation has been performed slowly, the remaining gold will have the form of distinct masses. gold appears black after parting; its parts have no adhesion together, because the silver dissolved from it has left many interstices. To give them more solidity, and improve their color, they are put into a test under a muffle, and made red-hot, after which they contract and become more solid, and the gold resumes its color and lustre. It is then called grain gold. If the operation has been performed hastily, the gold will have the appearance of black mud or powder, which, after well washing, must be melted. The silver is usually recovered by precipitating it from the aqua-fortis by means of pure copper, or by precipitation by muriatic acid and reduction. If the solution be perfectly saturated, no precipitation can take place till a few drops of aqua-fortis are added to the liquor. The precipitate of silver must be well washed with boiling water, and may be fused with nitre, or tested off with lead. Parting by Cementation. A cement is prepared, composed of 4 parts of bricks powdered and sifted; of 1 part of green vitriol calcined till it becomes red; and of 1 part of common salt. This is to be made into a firm paste with a little water. It is called the cement royal. the muriatic acld becomes concentrated by the heat and dissolves the silver alloyed with the geld This is a very troublesome process, though it sueceeds when the portion of silver is so small that it would be defended from the action of aqua-fortis by the superabundant gold; but is little used, except to extract silver, or base metals, from the surface of gold, and thus giving to an alloyed metal the color and appearance of pure gold. Pattinson's Process ver to the ton. For separating silver from lead ores, enables us to reduce profitably ores containing but 1 oz. of silIt depends upon the fact that an alloy of lead and silver when cooled, with occasional stirring, to near the point of solidification, crystallizes in part, and these crystals are found to contain much less lead than the original fused mass. Eight or ten cast-iron pots are arranged in line and heated. Into the centre one a charge, say 5 tons, of the original alloy is put; as the crystals form they are removed by means of a perforated ladle, and put in the pot to the right until about four-fifths have been removed; the remaining enriched lead is transferred to the pot to the left. This process is continued with the remaining pots, thus gradually enriching to the left and becoming poorer to the right. The rich alloy, termed lead riches, is then cupeiled. ALLOYS, OR COMPOUND METALS. Metals, in general, will unite with each other by fusion or amalgamation, and acquire new properties. Brass is a compound of copper and zine; and possesses a different color to either of the component parts. As metals fuse in different degrees of heat, care should be taken not to add those metals which fuse easily, to others which require a greater degree of heat, while they are too hot, because the former may evaporate and leave the compound imperfect. Or, if they are brought into fusion together, it should be under a flux to prevent the volatile metals from evaporating before the union is effected. Or-moulu-Mosaic Gold. Melt together equal parts of copper and zinc, at the lowest temperature that will fuse the former, stir them well to produce an intimate mixture of the metals, and add by degrees small quantities of zine; the alloy first assumes a yellow color like brass, on adding a little more zinc it becomes purple, and lastly perfectly white, which is the proper appearance of the desired product when fused. The quantity of zinc to be used altogether, should be from 52 to 55 parts out of the hundred. Talmi Gold. A beautiful gold-colored alloy, sold under the above name, gives on analysis: Copper, 86.4; zinc, 12.2; tin, 1.1; iron, 0.3. The presence of the iron was probably accidental. Queen's Metal. Melt together 44 lbs. of tin, lb. of bismuth, lb. of antimony, and lb. of lead. A very excellent alloy will be formed by using these proportions; it is used for making tea-pots and other retain their brilliancy to the last. vessels which are required to imitate silver. They The gold to be cemented is reduced into plates as thin as money. At the bottom of the crucible or cementing pot, a stratum of cement, of the thickness of a finger, is put, which is covered with plates of gold; and so the strata are placed alternately. The whole is covered with a lid, which is luted with a mixture of clay and sand. This pot must be placed in a furnace or oven, heated gradually till it becomes red-hot, in which it must be continued during 24 hours. The heat must not melt the gold. The pot or crucible is then suffered to cool; and the gold carefully separated from the cement, and boiled at different times in a large Another. A very fine silver-looking metal is quantity of pure water. It is then assayed upon a touch-stone, or otherwise; and if it be not suffi-composed of 100 lbs. of tin, 8 of regulus of anticiently pure, it is cemented a second time. In mony, 1 of bismuth, and 4 of copper. this process the sulphuric acid of the calcined vitriol decomposes the common salt during the cementation, by uniting to its alkaline base, while Tombac. Melt together 16 lbs. of copper, 1 lb. of tin, and 1 lb. of zinc. adopt different compositions for stereotype plates. Some form an alloy of 8 parts of lead, 2 parts of antimony, and part of tin. Mode of Casting. For the manufacture of stereotype plates, plaster of Paris, of the consistence of a batter-pudding before baking, is poured over the letter-press page, and worked into the interstices of the types with a brush. It is then collected from the sides by a slip of iron or wood, so as to be smooth and compact. In about 2 minutes the whole mass is hardened into a solid cake. This cake, which is to serve as the matrix of the stereotype plate, is now put upon a rack in an oven, where it undergoes great heat, so as to drive off superfluous moisture. When ready for use, these moulds, according to their size, are placed in flat cast-iron pots, and are covered over by another piece of cast-iron perforated at each end to admit the metallic composi The best sort of pewter consists of 100 parts of tion intended for the preparation of the stereotype tin, and 17 of regulus of antimony. Hard Pewter. Melt together 12 lbs. of tin, 1 lb. of regulus of antimony, and 4 oz. of copper. Common Solder. Put into a crucible 2 lbs. of lead, and when melted throw in 1 lb. of tin. This alloy is that generally known by the name of solder. When heated by a hot iron and applied to tinned iron with powdered rosin, it acts as a cement or solder; it is also used to join leaden pipes, etc. Hard Solder. Melt together 2 lbs. of copper, and 1 lb of tin. Melt together 2 lbs. of tin, and 1 of lead. The lining of tea chests makes a good solder for tin ware, being made of tin and lead in about the proper proportions. Gold Solder Hard-4 parts of silver to 1 of copper. Soft2 parts of silver to 1 of brass wire. Shot Metal. Lead, 1000 parts; metallic arsenic, 3 parts. plates. The flat cast-iron pots are now fastened in a crane, which carries them steadily to the metallic bath, or melting pot, where they are immersed and kept for a considerable time, until all the pores and crevices of the mould are completely and accurately filled. When this has taken place the pots are elevated from the bath by working the crane, and are placed over a water trough, to cool gradually. When cold the whole is turned out of the pots, and the plaster being separated by hammering and washing, the plates are ready for use; having received the most exact and perfect impression. White Metal. Melt together 10 oz. of lead, 5 oz. of bismuth, and 4 drs. of regulus of antimony. Another.-Melt together 2 lbs. of regulus of antimony, 8 oz. of brass, and 10 oz. of tin. Common Hard White Metal Melt together 1 lb. of brass, 1 oz. of spelter, andoz. of tin. Tutenag. Melt together 2 parts of tin and 1 of bismuth. Put into a crucible 4 oz. of bismuth, and when in a state of fusion throw in 24 oz. of lead, and 14 oz. of tin; these metals will combine, forming an alloy fusible at the temperature of boiling water. Mould this alloy in bars, and take them to a silPut into a crucible 10 lbs. of lead, and when it versmith's to be made into a half-a-dozen teais in a state of fusion, throw in 2 lbs. of antimony; spoons. If one of these be given to a stranger to these metals, in such proportions, form the alloy stir his tea, as soon as it is poured from the teaof which common printing types are made. The pot, he will be not a little surprised to find the antimony gives a hardness to the lead, without spoon melt in the tea-cup. which the type would speedily be rendered useless in a printing press. Different proportions of lead, copper, brass, and antimony, frequently constitute this metal. Every artist has his own proportions, so that the same composition cannot be obtained from different foundries; each boasts of the superiority of his own mixture. Small Types and Stereotype Plates. Melt 9 lbs. of lead, and throw into the crucible 2 lbs. of antimony and 1 lb. of bismuth; these metals will combine, forming an alloy of a peculiar quality. This quality is expansion as it cools, it is therefore well suited for the formation of small printing types (particularly when many are oast together to form stereotype plates), as the whole of the mould is accurately filled with the alloy; consequently there can be no blemish in the letters. If a metal or alloy liable to contract in cooling were to be used, the effect of course would be very different. Another. The proprietors of different foundries The fusibility of this alloy is certainly surprising, for the fusing temperature of each of its components, singly, is higher than twice that of boiling water. Bismuth fuses at 476°, lead at 612°, and tin at 442°; whilst water boils at 212°. Another.-Melt together 1 oz. of zinc, 1 oz. of bismuth, and 1 oz. of lead. This alloy will be found to be remarkably fusible (although each of the metals, separately, requires considerable heat to melt it), and will melt even in hot water; it will likewise remain in a fused state on a sheet of paper, over the flame of a lamp or candle. Both of these alloys expand on cooling, and are well adapted for taking casts of medals, etc. Wood's (patent) Fusible Metal Melts between 150° and 160° Fahr. It consiste of 3 parts cadmium, 4 tin, 8 lead, and 15 bismuth. It has a brilliant metallic lustre, and does not tarnish readily. Casts from Fusible Metal. A combination of 3 parts of lead, with 2 of tim and 5 of bismuth, forms an alloy which melts at the temperature of 197° Fahr. In making casts with this and similar alloys it is important to use the metal at a temperature as low as possible; as, if but a few degrees elevated, the water which adheres to the things from which casts are to be taken forms vapor, and produces bubbles. The fused metal must be allowed to cool in a teacup until just ready to set at the edges, and then pour it into the moulds, procuring in this way beautiful casts from moulds of wood, or of other similar substances. When taking impressions from gems, seals, etc. the fused alloy should be placed on paper or paste-board, and stirred about till it becomes pasty, from cooling, at which moment the gem, die, or seal should be suddenly stamped on it, and a very sharp impression will then be obtained. Metallic Injection. Melt together equal parts of bismuth, lead, and tin, with a sufficient quantity of quicksilver. This composition, with the addition of a small proportion of mercury, is used for injecting the vessels of many anatomical preparations; also for taking correct casts of various cavities of the body, as those of the ear. The animal structure may be corroded and separated by means of a solution of potassa in water, and the metallic cast will be. preserved in an isolated state. For Cushions of Electrical Machines. Melt together in a crucible 2 drs. of zine and 1 of tin; when fused, pour them into a cold crucible, containing 5 drs. of mercury. The mercury will combine with those metals and form an alloy (or amalgam, as it is called) fit to be rubbed on the cushions which press the plate or cylinder of an electrical machine. Before the amalgam is applied it is proper to rub the cushion with a mixture of tallow and beeswax. For Varnishing Figures. weights are then to be placed on the glass, and in a little time the quicksilvered tin foil adheres so firmly to the glass that the weights may be removed without any danger of its falling off. The glass thus coated is a common looking-glass. About 2 oz. of mercury are sufficient for covering 3 square feet of glass. The success of this operation depends much on the clearness of the glass; and the least dirt or dust on its surface will prevent the adhesion of the amalgam or alloy. Liquid Foil for Silvering Glass Globes. Melt together 1 oz. of clean lead, and 1 oz. of fine tin, in a clean iron ladle; then immediately add 1 oz. of bismuth. Skim off the dross, remove the ladle from the fire, and before it sets add 10 oz. of quicksilver. Now stir the whole carefully together, taking care not to breathe over it, as the fumes of the mercury are very pernicious. Pour this through an earthen pipe into the glass globe, which turn repeatedly round. Another. To 4 oz. of quicksilver add as much tin-foil as will become barely fluid when mixed. Let the globe be clean and warm, and inject the quicksilver by means of a pipe at the aperture, turning it about till it is silvered all over. the remainder run out, and hang the globe up. Let Another. For this purpose 1 part of mercury and 4 of tin have been used; but if 2 parts of mercury, 1 of tin, 1 of lead, and 1 of bismuth are melted together, the compound which they form will answer the purpose better. Either of them must be made in an iron ladle, over a clear fire, and must be frequently stirred. Martin's Process for Silvering Glass. Prepare, 1. A solution of 10 grammes of nitrato of silver in 100 grammes of distilled water. 2. Take solution of ammonia of 13° Cartier's areometer. 3. A solution of 20 grammes of pure caustic soda in 500 grammes of distilled water. 4. A so Fuse oz. of tin with the same quantity of bis-lution of 25 grammes of ordinary white sugar in muth in a crucible; when melted add 1⁄2 oz. of mercury. When perfectly combined take the mixture from the fire and cool it. This substance, mixed with the white of an egg, forms a very beautiful varnish for plaster figures, etc. Moirée Metallique.-A Method of Ornamenting the Surface of Tin Plate by Acids. The plates are washed by an alkaline solution, then in water, heated, and sponged or sprinkled with the acid solution. The appearance varies with the degree of heat and the nature and strength of the acids employed. The plates, after the application of the acids, are plunged into water slightly acidulated, dried, and covered with white or colored varnishes. The following are some of the acid mixtures used: Nitro-muriatic acid, in different degrees of dilution; sulphuric acid, with 5 parts of water; 1 part of sulphuric acid, 2 of muriatic acid, and 8 of water; a strong solution of citric acid; 1 part nitric acid, 2 sul phuric, and 18 of water. Solution of potash is also used. To Plate Looking-glasses. This art is erroneously termed silvering, for, as will be presently seen, there is not a particle of silver present in the whole composition. On tin-foil, fitly disposed on a flat table, mercury is to be poured, and gently rubbed with a hare's-foot: it soon unites itself with the tin, which then becomes very splendid, or, as the workmen say, is quickened. A plate of glass is then cautiously to be slid upon the tin-leaf, in such a manner as to sweep off the redundant mercury which is not incorporated with the tin; leaden 200 grammes of distilled water. Pour into this 1 cubic centimetre of nitric acid, of 36°, and boil for 20 minutes; then make up the volume of 500 cubic centimetres with distilled water and 50 cubic centimetres of alcohol at 36°. This done, prepare an argentiferous solution, by mixing in a flask 12 cubic centimetres of solution 1, then 8 cubic centimetres of solution 2, then 20 centimetres of solution 3; and, lastly, make up a volume of 100 centimetres by 60 centimetres of distilled water. If the directions have been properly observed the liquid will remain limpid, and a drop of solution of nitrate of silver will produce a permanent precipitate. After being left quiet for 24 hours the Clean the surface to be solution is ready for use. silvered with a cotton plug moistened with a few drops of nitric acid; then wash with distilled water, drain, and place it on supports on the surface of a bath composed of the argentiferous liquid, to which has been added 1-10th or 1-12th of the solution of sugar (4). Under the influence of diffused light the liquid becomes yellow, then brown, and, after from 2 to 5 minutes, the whole surface of the glass will have been silvered. After 10 or 15 minutes it will have attained the required thickness. Wash first with ordinary water, then with distilled water; drain, dry, and polish with rouge on chamois. (A table of French Weights and Measures will be found at the end of the volume.) Mode of Repairing the Silvering of Looking-glasses. Uncover and clean the damaged spot by very careful rubbing with fine cotton until there is no trace of grease or dust; then with the point of a Specula of Telescopes. knife cut the size of the required piece on the sil- | times, been generally used in the formation of vering of another glass; a small globule of mer- busts, medals and statues. cury (the size of a pin's head for a surface the size of the finger nail) is dropped upon the cut piece. The mercury penetrates as far as the cut, and allows the piece to be removed. It is then gently pressed on the spot with a piece of cotton. Bath-metal. Melt 7 lbs. of copper, and when fused add 3.bs. of zinc and 4 lbs. of tin. These metals will combine to form a beautiful alloy of great lustre, and of a light yellow color, fitted to be made into specula for telescopes. Mr. Mudge used only Melt together 1 lb. of brass and 4 oz. of spelter. copper and grain tin, in the proportion of 2 lbs. to 144 oz. Brass. Put 44 lbs. of copper into a crucible, expose it to heat in a furnace, and when perfectly fused add 14 lbs. of zinc. The metals will combine, forming that generally used alloy called brass. Another. For brass which is to be cast into plates, from which pans and kettles are to be made, and wire is to be drawn, braziers use calamine of the finest sort instead of pure zinc, and in a greater proportion than when common brass is made; generally 56 lbs. of calamine to 34 lbs. of copper. Old brass, which has frequently been exposed to the action of the fire, when mixed with the copper and calamine, renders the brass far more ductile and fitter for the making of fine wire than it would be without it. Pinchbeck. Put into a crucible 5 oz. of pure copper; when it is in a state of fusion add 1 oz. of zinc. These Gun-metal. Melt together 112 lbs. of Bristol brass, 14 lbs. of spelter, and 7 lbs. of block tin. Another.-Melt together 9 parts of copper and part of tin; the above compounds are those used in the manufacture of small and great brass guns, swivels, etc. The pieces of ordnance used by the besiegers at the battle of Prague, were actually melted by the frequency of the firing; the mixture of which they were made contained a large portion of lead; it would have been less prone to melt, and conseA quently preferable, had it contained none. mixture of copper amd tin is preferred to pure copper, not only for the casting of cannon, but of statues, etc., for pure copper, in running through the various parts of the mould, would lose so much of its heat as to set, or become solid too soon. Austrian Gun-metal (Aich's Metal), metals combine, forming an alloy not unlike jew-Remarkable for great strength, being stronger eller's gold; pour it into a mould of any shape. This alloy is used for inferior jewellery. Some use only half this quantity of zinc, in which proportion the alloy is more easily worked, especially in the making of jewellery. Another.-Melt together 1 oz. of brass with 1 or 2 oz. of copper, fused under a coat of charcoaldust. Oréide, a New Brass. than gun-metal or wrought-iron, consists of copper, 55.04; zinc, 42.36; tin, .83; iron, 1.77. Aluminum Bronze Resembles gold in appearance; is said to be twice as strong as the best gun-metal; as light as wrought-iron; is not easily tarnished. It is easily stamped and engraved. It is composed of 10 parts of aluminum and 90 of copper. It requires to be re-melted, as the first melting is brittle. Babbitt's Anti-friction Metal. Mix together 24 parts of copper, 24 of tin and The tin, best quality of Bancoa, 8 of antimony. is to be added gradually to the melted composition. Bell-metal. Melt together 6 parts of copper and 2 of tin. These proportions are the most approved for bells throughout Europe and in China. M. M. Mourier and Vallent, of Paris, have succeeded in making an alloy which imitates gold sufficiently near to merit the name Oréide. The properties are as follows: Pure copper, 100 parts, by weight; zinc, 17; magnesia, 6; sal ammoniac, 3.6; quicklime, 1.80; tartar of commerce, 9. The copper is first melted, then the magnesia, sal ammoniac, lime and tartar in powder, little by little; the crucible is briskly stirred for about an hour, so as to mix thoroughly, and then the zinc is added in small grains by throwing it on the surface Another. Some bells are made in the proporand stirring until it is entirely fused; the crucible tion of 10 parts of copper to 2 of tin. It may be is then covered and fusion maintained for about 35 in general observed, that a less proportion of tin minutes; the crucible is then uncovered, skimmed is used for making church bells than clock bells, carefully and the alloy cast in a mould of damp and that a little zine is added for the bells of resand or metal. The oréide melts at a tempera-peating watches and other small bells. ture low enough to allow its application to all kinds of ornamentation; it has a fine grain, is malleable, and capable of taking the most brilliant polish; when, after a time, it becomes tarnished from oxidation, its brilliancy may be reIf the zinc is stored by a little acidulated water. replaced by tin, the metal will be still more brilliant. Prince's Metal. Melt together 3 oz. of copper, and 1 oz. of zinc; or, 8 oz. of brass and 1 oz. of zinc. Another.-Melt in a crucible 4 oz. of copper, and when fused, add 2 oz. of zinc; they will combine, and form a very beautiful and useful alloy, called Prince Rupert's metal. Bronze. Melt in a clean crucible 7 lbs. of pure copper; when fused, throw into it 3 lbs. of zinc and 2 lbs. of tin. These metals will combine, forming bronze, which, from the exactness of the impression which it takes from a mould, has, in ancient and modern Blanched Copper. Melt together 8 oz. of copper and oz. of neutral arsenical salt, fused together, under a flux composed of calcined borax, charcoal dust, and finely-powdered glass. Composition of Ancient Statues. According to Pliny, the metal used by the Romans for their statues, and for the plates on which they engraved inscriptions, was composed in the following manner: They first melted a quantity of copper, into which they put a third of its weight of old copper, which had been long in use; to every 100 lbs. weight of this mixture they added 12 lbs. of an alloy composed of equal parts of lead and tin. Muntz Metal Can be rolled and worked at a red heat. It con- Melt together 8 oz. of brass and 5 of pelter. |