IX.—On certain sources of loss of precious metal in some operations of assaying
Quarterly Journal of the Chemical Society of London
IX.--Om certain sources sf loss of Precious Hetal in some operations of Assaying. BY G. H. MAKINS. IN the assay of specimens of alloyed gold, the degree of heat used in the first operation, viz., cupellation (when this is carefully performed), is usually somew hat varied, according to presupposed proportions in the alloy,-for example, a much lower temperature being suBicient where the gold is only associated with silver, than where it is also mixed with oxidisable metals, which latter have to
... ch latter have to be separated entirely by this first operation, About five years since, I chanced to have before me some 2 0 assays of gold, wherein the silver also had to be estimated, and in which, for other reasons, an extraordinary degree of heat was required to be employed ; and as I made simultaneously with these, several synthetieal prods, I was milch struck by the great extent of loss of gold and silvep; and satisfied that it could riot be eutirely due to what is known amongst assayers as cupel absorption, I determined upon examinirrg scme af the contents of an iron flue of a onpel furnace, which passed from its hood into a chimney, iu order to see if gold had been volatilized along with other metals, and if so, to what extent.