Note 40 — BOOK X.

[Pg 484][40] The refining of silver in "tests" (Latin testa) is merely a second cupellation, with greater care and under stronger blast. Stirring the mass with an iron rod serves to raise the impurities which either volatilize as litharge or, floating to the edges, are absorbed into the "test." The capacity of the tests, from 15 librae to 50 librae, would be from about 155 to 515 ozs. Troy.