Chapter CAPELAN to CARAT of C by The Hobson Jobson Dictionary

carat was=1/144 of an ounce. In the passage from St. Isidore quoted below, the cerates is distinct from the siliqua, and = 1½ siliquae. This we cannot explain, but the siliqua Graeca was the [Greek Text] keration; and the siliqua as 1/24 of a solidus is the parent of the carat in all its uses. [See Prof. Gardner, in Smith, Dict. Ant. 3rd ed. ii. 675.] Thus we find the carat at Constantinople in the 14th century=1/24 of the hyperpera or Greek bezant, which was a debased representative of the solidus ; and at Alexandria 1/24 of the Arabic dinar, which was a purer representative of the solidus. And so, as the Roman uncia signified 1/12 of any unit (compare ounce, inch), so to a certain extent carat came to signify 1/24. Dictionaries give Arab. kirrat as “1/24 of an ounce.” Of this we do not know the evidence. The English Cyclopaedia (s.v.) again states that “the carat was originally the 24th part of the marc, or half-pound, among the French, from whom the word came.” This sentence perhaps contains more than one error ; but still both of these allegations exhibit the carat as 1/24th part. Among our goldsmiths the term is still used to measure the proportionate quality of gold ; pure gold being put at 24 carats, gold with 1/12 alloy at 22 carats, with ¼ alloy at 18 carats, &c. And the word seems also (like Anna, q.v.) sometimes to have been used to express a proportionate scale in other matters, as is illustrated by a curious passage in Marco Polo, quoted below.

The carat is also used as a weight for diamonds. As 1/144 of an ounce troy this ought to make it 3 1/3 grains. But these carats really run 151 ½ to the ounce troy, so that the diamond carat is 3 1/6 grs. nearly. This we presume was adopted direct from some foreign system in which the carat was 1/144 of the local ounce. [See Ball, Tavernier, ii. 447.]

c. A.D. 636.—“Siliqua vigesima quarta pars solidi est, ab arboris semine vocabulum tenens. Cerates oboli pars media est siliquã habens unam semis. Hanc latinitas semiobulu vocat ; Cerates autem Graece, Latine siliqua cornuu interpretatur. Obulus siliquis tribus appenditur, habens cerates duos, calcos quatuor.”—Isidori Hispalensis Opera (ed. Paris, 1601), p. 224.

1298.—“The Great Kaan sends his commissioners to the Province to select four or five hundred…of the most beautiful young women, according to the scale of beauty enjoined upon them. The commissioners…assemble all the girls of the province, in presence of appraisers appointed for the purpose. These carefully survey the points of each girl.… They will then set down some as estimated at 16 carats, some at 17, 18, 20, or more or less, according to the sum of the beauties or defects of each. And whatever standard the Great Kaan may have fixed for those that are to be brought to him, whether it be 20 carats or 21, the commissioners select the required number from those who have attained to that standard.”—Marco Polo, 2nd ed. i. 350–351.

1673.—“A stone of one Carrack is worth 10l.”—Fryer, 214.

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