The Process of Assay.
The two essential things regarding every piece of metal offered in payment of any dues were, first, the weight or quantity, next, the fineness or purity of the same. The process of weighing even the baser metals used in coining must be conducted by the careful use of accurate scales, with precise notes of the results. In precious metals, gold, silver, and their high grade alloys, a very small variation in the fineness makes a great difference in the value. Nothing is more essential than the accurate determination of the weight of the sample and of the metal obtained from it. It requires keen sight and most delicate adjustment in the hand which manipulates the Lilliputian scales of an Assayer’s table. The smallest weight used in the Mint is found in the Assay Room; it is the thirteen-hundredth part of a grain, and can scarcely be seen with the naked eye, unless on a white ground. The Assay Department is strictly a technical and scientific branch of the service. It has been practically under one regime, for the last fifty years. There have been but three Chief Assayers in that time, the only removals being by death, the only appointments by promotion. Its workmen are all picked men, selected from other parts of the Mint for special fitness and good character.