ASSAY FURNACE.
PORTABLE ASSAY FURNACE.
Crucibles of black lead, French clay, Hessian sand, and quicklime are necessary to hold the assay.
CRUCIBLES.
SCORIFIER.
STEEL CUPEL MOULD.
Roasting dishes, scorifiers and cupels are required. The cupel is made of the ashes of burnt bone, and it is better to make them on the spot, as the bone ash may be carried anywhere without damage, whereas the cupels are very fragile. The bone ash is moistened with water, stamped in a cupel mould, and allowed to dry slowly. A good one will absorb its own weight of lead, but it is better to calculate on its absorbing but three-quarters of that amount.
SCORIFICATION FURNACE.
