Assaying
the estimation of the amount of pure metal, and especially of the precious metals, in an ore or alloy.
In the case of silver, the assay is either by the dry or by the wet process. The dry process is called cupellation, from the use of a small and very porous cup, called a cupel, formed of well burned and finely ground bone ash made into a ASSAY OFFICES ASSIGNATS paste with water. The cupel, being the branches being commonly spoken of thoroughly dried, is placed in a fire clay oven. This oven, called a muffle, is set in a furnace, and when it is at a red heat the assay, consisting of a small weighted portion of the alloy wrapped in sheet lead, is laid upon the cupel. The heat causes the lead to volatilize or comas the Senate and the House (of Representatives).