AbstractsBiology & Animal Science

"It is known that the lead button which we obtain from fire assay for silver does not represent the true value of the ore. There is always a loss of silver. To investigate the effect of varying the fluxes on the loss in silver is the object of the first part of this thesis...Silver ores often contain copper, part of which, during the fusion, enters the lead button, causing trouble during cupellation, since it must be done at a high temperature. It is, then, important to keep copper out of the lead button. The presence of litharge in the fusion tends to accomplish this. The purpose of the second part of this work is to study the effect of varying the amounts of litharge, in the charges, on the copper contents of the lead" – p. [1], 5.