5 gram of borax. Scorify, clean the slag by adding anthracite after
the "eye" has closed in: cupel the button of lead. Weigh the button of
silver, make the necessary corrections, and calculate to ounces to the
ton.
The determination may also be made by cupelling the button of lead got
in the dry lead assay.
A sample of galena determined by the three methods gave the following
results:--
By pot assay 7.18 ozs. per ton.
" scorification 7.02 "
" lead assay 6.72 "
~Determination of Silver in an Ore.~ _By Pot Assay._--Take 20 grams of
the powdered ore and mix with 30 grams of soda, 40 grams of red lead,
and 5 grams of borax, as also with from 2 to 3 grams of flour. Fuse:
pour. Clean the slag by fusing with 20 grams of red lead and two grams
of flour. Cupel the buttons of lead; weigh; make the necessary
corrections, and calculate to ounces to the ton.
_By Scorification._--Take 5 grams of the powdered ore, 50 grams of lead,
and 0.5 gram of "soda" or borax. Scorify. Clean the slag by fusing in a
crucible as in the pot assay. Cupel, &c.
_Examples._--_By Pot Assay._--Ore taken 20 grams.
Silver got 0.2893 gram
Silver from slag 0.0060 "
Silver lost in cupellation 0.0100 "
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