the weight which expresses the degree of fineness of gold. The word is also written *caract*, *carat*, *karact*, and *karrat*. Its origin is contested; but the most probable opinion is that of Kennet, who derives it from *carecta*, a term which anciently denoted any weight, and came afterwards to be appropriated to that which expresses the fineness of gold and the gravity of diamonds.

Carats are not real determinate weights, but only imaginary. The whole mass, whatever be the weight, is conceived to be divided into twenty-four carats; and as many twenty-fourth parts as it contains of pure gold, it is called gold of so many carats, or so many carats fine. Thus gold of eighteen carats is a mixture, of which eighteen parts are pure gold, and the other six of inferior metal.

Carat is also a certain weight which goldsmiths and jewelers use for weighing precious stones and pearls. In this sense the word is supposed by some to be derived from the Greek *στροφόν*, a fruit which in Latin is called *silique*, the *carob bean*, each of which may weigh above four grains of wheat; and hence the Latin *silique* has been used for the weight of four grains. This carat weighs four grains; but they are sometimes lighter than the grains of other weights. Each of these grains is subdivided into $\frac{1}{2}$, $\frac{1}{4}$, $\frac{1}{8}$, $\frac{1}{16}$, &c. See Weights and Measures.

CARAUSIUS, Emperor of Britain. See Britain, p. 380; and ALLECTUS.