bismuth. The alloy containing 10 per cent. bismuth is hard, malleable, takes a fine polish, is unattacked by nitric acid, and not blackened by sulphuretted hydrogren. We say it was malleable because it could be worked to a certain extent under the hammer, and we thought it could be easily drawn out, but in spite of frequent annealings it split in all directions and we had to stop working it. We tried, by diminishing the per cent. of bismuth, to take away this bad quality, and to this end prepared alloys with 5, 3, 2.5, and 0.5 per cent. of the latter, but without obtaining satisfactory results.

Watts One-tenth of one per cent. of bismuth renders aluminium so brittle that it cracks under the hammer after being repeatedly annealed.

ALUMINIUM AND NICKEL.

Tissier: The alloy with 50 per cent. nickel was made by melting together the metals in equal proportions under NaCl; the heat evolved was sufficient to raise the mass to incandescence. This alloy remained pasty at the temperature of melting copper. It is so brittle that it pulverizes under the hammer. By melting proper proportions of this alloy with more aluminium, an alloy with 25` per cent. nickel was produced. This is less fusible than aluminium, and as brittle as the 50 per cent. alloy. By melting some 25 per cent. nickel alloy

with aluminium, a 5 per cent. nickel alloy was obtained. This is much less brittle than the preceding, but is still very far from being easy to work. From the 5 per cent. alloy one with 3 per cent. was made. With this amount of nickel the aluminium acquired much hardness and rigidity, and was easy to work. A curious fact with this. alloy is that it may be melted on a plate of aluminium, showing its fusion point to be less than that of pure aluminium, the reverse effect to what iron produces, which if present in the same proportion would diminish the fusibility of the aluminium. To sum up, the action of nickel on aluminium is much analogous to that of iron, for nickel, like iron, produces crystalline alloys with aluminium, and if employed with care gives to it certain desirable qualities such as hardness, elasticity, etc.

Mierzinski: To alloy aluminium with nickel a certain limiting quantity of nickel must not be exceeded. When the latter is present less than 3 per cent., it behaves similarly to iron in improving the qualities of the aluminium in many ways, especially in hardness and elasticity. More than 3 per cent. makes the aluminium brittle and unworkable.

Argentan has a beautiful color, and takes a high polish, it contains-

Cu.

Ni.

Al.

70

23

7

Tissier: Silver is the metal which seems most useful in improving aluminium. Five per cent. silver gives to aluminium elasticity which is wanting in pure aluminium, increases its hardness and its capability of being polished, and does not injure its malleability. We have sold a quantity of these alloys, the properties of which we will describe. All the alloys up to 50 per. cent of silver are more fusible than aluminium, the fusibility increasing with the amount of silver. The alloy with 33 per cent. silver is fusible enough to serve for a solder; but, like the alloys of aluminium with zinc and tin, it casts with difficulty and makes a brittle joint. With 10 per cent. silver the aluminium will not stand under the hammer. The 50 per cent. alloy breaks like those of copper. The presence of silver in aluminium can always be recognized by the action of the alloy on a moderately concentrated solution of caustic potash. Aluminium whitens in this solution, but, if it contains silver, this being exposed by the dissolving away of the aluminium gives the surface a black color. By introducing 5 per cent. of aluminium into silver

the latter acquires the hardness of silver coin, the alloy takes a beautiful polish, does not contain as alterable a metal as copper, and contains 95 per cent. of silver instead of 90. This alloy is easily distinguished from the alloy into which copper enters by the test with nitric acid, which whitens instead of blackening it.

Deville: A few per cent. of silver will take away from aluminium all its malleability. However, the alloy with 3 per cent. is used by M. Christofle for casting objects of art; and the alloy with 5 per cent. to make knife blades, and it may be worked like pure aluminium. It has, moreover, the color and lustre of silver, and is not tarnished by sulphuretted hydrogen.

Kerl and Stohman: According to Hirzel, the alloy containing 20 per cent. aluminium is very porous, silver-white, tarnishing in the air, sp. gr. 6.733. AlAg2, containing 11.11 per cent. aluminium is also silver-white, a little porous, tarnishes in the air, sp. gr. 8.744. AlAg', containing 5.9 per cent. aluminium is pure silver-white, very malleable, forgeable, tarnishing in the air, sp. gr. 9.376.

Fremy The alloys of aluminium and silver are easy to form by direct fusion of the two metals; their hardness is generally superior to that of aluminium, but, nevertheless, they are quite as easy to work, and in some cases more fusible than it. Debray states that the 50 per cent. alloy is as hard as bronze.

Mierzinski: Five per cent. of silver makes aluminium elastic and as hard as coin silver, but not brittle. This alloy is workable like pure aluminium, takes a fine polish, is light, not magnetic, does not rust, and has the color of pure silver, whose place it can take for many purposes. However, the assertion that this or any other alloy of silver and aluminium is not attacked by hydrogen sulphide is incorrect and untenable, since, according to careful experiments, these alloys are attacked quicker and more actively by it than pure silver. This alloy is used for watch-springs, dessert-spoons, etc., on account of its hardness and elasticity. The alloy with 3 per cent. silver has a very fine silver color. The 50 per cent. alloy is as hard as bronze, but so brittle that it cannot be pressed; all the alloys with over 10 per cent. silver up to the 50 per cent. alloy are brittle and cannot be worked with a hammer.

"Tiers Argent" is an alloy of two-thirds aluminium and one-third silver, which was made homogeneous at first with some difficulty but is now easily made. Spoons, forks, and salvers of this alloy leave nothing to be desired. It possesses a hardness superior to silver, and can be easily engraved.*

Cowles Bros. state that what is generally known and sold as aluminium silver is an alloy of alu

* Chem. News, xvi. 289.