Reactions of gold and silver in cyanide solutions.

The chemistry, of the cyanides in general, dates from the early eighteenth century, but the action of aqueous solutions of cyanide on gold was not noted until 1840. At that time the Elkingtons (20) obtained a patent for gold plating electrolytically, using for the electrolyte a solution made by dissolving gold in potassium cyanide with the aid of an electrio current. [...