USEFUL RECEIPTS. Compounds of Metals. Fusible Metal.-No. 1. 4 oz. of bismuth, 24 oz. of lead, and 1 oz. of tin. Put the bismuth into a crucible, and, when it is melted, add the lead and tin. This will form an alloy fusible at the temperature of boiling This alloy is so very fusible, that it will remain in a state of fusion if put on a sheet of paper, and held over the flame of a candle or lamp. -3 parts of lead, 2 parts of tin, and No. 3. 5 parts of bismuth, will form an alloy fusible at 197° Fahrenheit, peculiarly applicable to casting, or the taking of impressions from gems, seals, &c. In making casts with this and similar alloys, it is necessary to use the metal at as low a temperature as possible; otherwise, the water adhering to the things from which the casts are to be taken, forms vapour, and produces bubbles. The fused metal should be poured into a tea cup, and allowed to cool, till just ready to set at the edges, when it must be poured into the mould. In taking impressions from gems, seals, &c. the fused alloy should be placed on paper or pasteboard, and stirred about till it has, by cooling, attained the consistence of paste, at which moment the die, gem, or seal should be stamped on it, and a very sharp impression will then be obtained. Bath Metal, is a mixture of 4 oz. of zinc, with 1 lb. of brass. But brass that is to be cast into plates, from which pans and kettles are to be made, and wire is to be drawn, must, instead of using the zinc in a pure state, be composed of 56 lb. of the finest calamine, or ore of zinc, and 34 lb. of copper. Old brass, which has been frequently exposed to the action of 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; but the German brass, particularly that of Nuremburgh, is, when drawn into wire, said to be far preferable to any made in England, for the strings of musical instruments. Pinchbeck.-No. 1. 5 oz. of pure copper, and 1 oz. of zinc. The zinc must not be added till the copper is in a state of fusion. Some use only half this quantity of zinc, in which proportion the alloy is more easily worked, especially in the making of jewellery. No. 2.1 oz. of brass, In this last, the copper must be fused before the zinc is added. When they have combined, a very beautiful and useful alloy is formed, called Prince Rupert's metal. Bell Metal.-No. 1. 6 parts of copper, and These proportions are the most approved, for bells, throughout Earope, and in China. In the union of the two metals, the combination is so complete, that the specific gravity of the alloy is greater than that of the two metals in an uncombined state. No. 2.10 parts of copper, and It may, in general, be observed, that a less proportion of tin is used for making church-bells than clock bells; and that a little zinc is added for the bells of repeating watches, and other small bells. Tutania, or Britannia Metal.-No. 1. 4 oz. of plate brass, and 4 oz. of tin; when in fusion, add 4 oz. of bismuth, and 4 oz. of regulus of antimony. This is the composition, or hardening, that is to be added, at discretion, to melted tin, until it has acquired the requisite degree of colour and hardness. No. 2.-Melt together, 2 lb. of plate brass. 2 lb. of tin, 2 lb. of bismuth, 2 lb. regulus of antimony, 2 lb. of a mixture of copper and arsenic, either by cementation or melting. This composition is to be added, at discretion, to melted tin. The iron or steel must be heated to a white heat, and the antimony and nitre must be added in small portions. Melt and harden 1 lb. of tin with 2 oz. of this compound. No. 2.-Melt together, 4 oz. of antimony, 1 oz. of arsenic, and 2 lb. of tin. The first of these Spanish alloys would be a beautiful metal if arsenic were added. Engestroom Tutania. 4 parts copper, 8 parts regulus of antimony, and 1 part bismuth, When added to 100 parts of tin, this compound will be ready for use. Queen's Metal.-No. 1. 44 lb. of tin, lb. bismuth, lb. antimony, and This alloy is used for the making of tea-pots, and other vessels, which are required to imitate silver. It retains its lustre to the last. No. 2.-100 lb. of tin, 8 lb. regulus of antimony, 1 lb. bismuth, and 4 lb. copper. The copper must be fused in the crucible before the zinc is added. This alloy is of a reddish colour, and possesses more lustre, and is of greater durability, than copper. White Tombac. Copper and Put together in a crucible, and melted, covering the surface with mu riate of soda, to prevent oxidation, will form a white brittle alloy. Gun Metal.-No. 1. 112 lb. of Bristol brass, No. 2. 14 lb. zinc, and 7 lb. block tin. 9 parts copper, and The above compounds are those used in the manufacture of small and great brass guns, swivels, &c. Blanched Copper. 8 oz. of copper, and oz. of neutral arsenical salt, fused together, under a flux composed of calcined borax, charcoal dust, and fine powder glass. Specula of Telescopes. 7 lb. of copper, and when fused, add 4 lb. of tin. These metals will combine and form a beautiful alloy of great lustre, and of a light yellow colour, fitted to be made into specula for teles copes. Mr. Mudge used only copper and grain tin, in the proportion of two pounds to fourteen and a half ounces. Kustitien's Metal for Tinning. To 1 lb. of malleable iron, at a white heat, add 5 oz. of regulus of antimony, and 24 lb. of the purest Molucca tin. This alloy polishes without the blue tint, and is free from lead or arsenic. Metal for Flute-key Valves. 4 oz. lead, and 2 oz. antimony, fused in a crucible, and cast into a bar, forms an alloy of considerable hardness and lustre. It is used by flute manufacturers (when turned into small buttons in a lathe,) for making valves to stop the keyholes of flutes... Printers' Types. 10 lb. of lead, and 2 lb. of antimony. The antimony must be thrown into the crucible when the lead is in a state of fusion. The antimony gives a hardness to the lead, without 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.-No. 1. 9 lb. of lead, and when melted, add 1 lb. of bismuth. This alloy expands as it cools, and is, therefore, well suited for the formation of sinall printing types, (particularly when many are cast 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. No. 2. -8 parts lead, 2 parts antimony, and 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 lie smooth and compact. In about two 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 with another piece of cast-iron, perforated at each end, to admit the metallic composition. intended for the preparation of the stereotype plates. The flat castiron 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 |