Determination of Silver in Galena. By Pot Assay.—Mix 20 grams of the powdered ore with 30 grams of red lead, 20 grams of soda, and 5 grams of borax, as also with from 7 to 10 grams of nitre. Fuse and pour. Clean the slag if the ore is rich. Cupel the buttons of lead. Make the usual corrections and calculate in ounces to the ton.
By Scorification.—Take 10 grams of the ore, 30 grams of lead, and 0.5 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 | " | |
| ——— | |||
| 0.3053 | " | ||
| Deduct silver in red lead | 0.0017 | " | |
| ——— | |||
| Silver in ore | 0.3036 | " | = 495.9 ozs. per ton. |
By Scorification.—Ore taken, 3 grams.