5948. Assayer's Gold Weights

5948. Assayer's Gold Weights. The richness or purity of gold is expressed in carats. Pure gold is spoken of as containing 24 carats, of 12 grains each; and any sample containing 12, 18, 22, or any other number of parts of pure gold, in 24 parts, is said to be of so many carats fine. In the process of assaying gold, the real quantity taken is very small, generally 6 or 12 grains; and this is termed the " assay pound." It is nominally subdivided into 24 carats, and each carat into 4 assay grains, and each grain into quarters. When the assay pound is only 6 grains, the quarter of the assay grain will only weigh the 1/64 of a grain; hence the most accurate system of weighing must be adopted.

5949. Assayer's Silver Weights

5949. Assayer's Silver Weights. The richness or purity of silver is either expressed in pennyweights or 1/1000. In the first case, it is supposed that the mass of silver to be examined consists of 12 equal parts, called pennyweights; so that if an ingot weighs an ounce, each of the parts will be 1/12 of an ounce. Hence, if the mass of silver be pure, it is called silver of 12 pennyweights; if it contain 1/12 of its weight of alloy, it is called silver of 11 pennyweights; if 2/12 of its weight be alloy, it is called silver of 10 pennyweights; and so on in proportion for other qualities. It must be observed here, that the assayers give the name pennyweight to a weight equal to 24 real grains, which must not be confounded with their ideal weights. The assayer's grains are called fine grains. An ingot of fine silver, or silver of 12 pennyweights, contains, then, 288 fine grains; if this ingot contain 1/288 of alloy, it is said to be silver of 11 pennyweights and 23 grains; if it contain 4/288 of alloy, it is said to be 11 pennyweights, 20 grains, etc.. The purity of silver is now more frequently expressed in 1/1000 , which admits of greater accuracy. 5950. Table for Converting Troy into Avoirdupois Weight.