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the gold is got out from the silver, without any additionalexpenee, in the fame operation by which the other goldis refined.

The most desirable proportions of the two metals are,one part of gold to three of silver, or one part of gold infour of the mixt, whence the process is sometimes calledquartation. When silver is added to gold, merely witha view to the purifying of the gold, these proportionsshould be kept to, as nearly as may be : for if the quan-tity of silver is less, the dissolution of it will not go onwith sufficient dispatch ; and is greater, it will occasionan unnecessary expenee of acid. Silver containing only asmall portion of gold is frequently submitted to this ope-ration : but in such cases, there are less expensive me-thods, which wi'll be described in the sequel of this sec-tion, for separating great part of the silver, so as to leaveonly a moderate quantity to be dissolved by the aqua fortis.

The metal, instead of being flatted into plates, as forthe parting assay, is reduced, with less trouble, into smallgrains, by melting it in a crucible, and pouring it intocold water. Some interpose a number of twigs, or a birchbroom, wetted, between it and the water, to divide thefluid metal into slender streams : Cramer describes a ma-chine for this purpose, composed of a wooden roller, laidacross the vessel of water, with its lower surface touchingthe water, covered all over with twigs, and made to turnby a handle. The granulation may be performed verysuccessfully without any contrivance of this kind, bynimbly stirring the water round, so as to communicate toit a rapid circular motion, and pouring in the metal atone side.

The granulated metal, with a suitable quantity of aquafortis, is put into parting glasses, which are commonlyabout twelve inches high, seven inches wide at the bot-5 torn.