This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1898 edition. Excerpt: ... vary in form according to the requirements of the trade. A shape common in the United 1 Hofman, op. cil. States is shown in Figs. 303 to 305, this having been found convenient for quick casting.1 One end is furnished with wheels, the other rests on the bearer b, a handle can be hooked through the hole c, the mould and bontents wheeled away, and the ingot tipped out, and the mould is then again ready for use. The composition of desilverised and refined American market lead is shown by the following analyses: --SILVER Physical Properties Silver has a pure white colour and a perfect metallic lustre. It is exceedingly malleable and ductile, being only second to gold in these properties; it is harder than gold, but softer than copper. The specific gravity of silver according to G. Rose lies between 10 514 and 10 619 at 14C, and according to Matthieson it is 10-468 at 13 C. It crystallises in the regular system. Its conductivity for heat stands to that of gold in the ratio of 100:102 8 (Despretz), 100:98 (Calvert and Johnson 100: 60 (Wiedemann and Franz). According to Regnault its specific heat is 0 05701 and according to Bunsen 0 0559. Silver is of all the metals the most perfect conductor of electricity; if its conductivity be taken as 100, that of gold is 73, and of copper 72 to 77 (Matthieson). It melts at about 1000C (according to Becquerel at 960CC, and according to Riemsdyck at 1040C).1 At high temperatures it volatilises, yielding a green vapour, and it can be distilled by means of the oxy-hydrogen blowpipe. When in the molten state, it possesses the power of absorbing oxygen from the air to the extent of 22 times its own volume, the gas being given out again on cooling with such vigour that the surface of the silver is thrown up into..