The Gay-lussac Method Of Silver Determination.

(New York Meeting, February, 1913) This old and well-known method of determining, silver is, in bullion work, so far superior to the furnace-assay that it is looked upon with reverential awe by many, if not by most, users, and its-ease of execution, with proper equipment, commends it highly where much commercial bullion work on silver is required. The method is so thoroughly well known that a, description of it here may seem to be unnecessary, but many thousands of determinations are annually made by it in the U. S. Mint Service and its practice is there reduced to an art. This is necessary both for the sake of economy of time, acid because high-grade work with it requires constant practice. It is useless for a person who uses it only occasionally to expect to attain high accuracy with it, without spending more time upon a determination than is warranted in a busy commercial laboratory. It is always employed in the Mint service whenever possible, but its chief field is in the determination of silver in standard silver (ingots and coin), which is 900 fine in silver and 100 fine in copper, and I shall first briefly outline its use on this metal and then take up various points in detail, especially as related to the accuracy of the results obtained.