METHOD OF OBTAINING SILVER.

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but it readily enters into combination with the greater numberof the other metals. With gold it forms what is termed gree?igold. Copper renders it harder without much impairing its duc-tility. Mercury and silver combine and form a crystallizable andfusible alloy. It unites with the rest of the metals except co-balt and nickel. It is oxidated and dissolved by several of theacids. The nitric acid attacks it rapidly in the cold. The sul-phuric acid requires a boiling heat. The muriatic acid does notact upon it. The acid solutions of silver are decomposable by thenlcalies, earths, and by the greater number of the metals.

METHOD OF OBTAINING SILVER.

Different methods are employed in different countries to ex-tract silver from its ores. In Mexico, Peru, See. the mineral ispounded, roasted, washed, and then triturated with mercury invessels filled with water. A mill is employed to keep the wholein agitation. The silver combines by that means with the mer-cury. The alloy thus obtained is afterwards washed, to separateany foreign matters from it, and then strained and pressedthrough leather. This being done heat is applied to drive offthe mercury from the silver, which is then melted and cast intobars or ingots.

In order to extract silver from sulphurated or vitreous silverore, the mineral is roasted, and then melted with lead and borax,or some other flux to assist the fusion. By the first operationthe sulphur is volatilized, and by the second the silver is ob-tained, though for the most part alloyed with the other metals,from which it is separated by cupellation, or fusion with lead orbismuth.

Vol. II.

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