a gold coin, worth 25 shillings; so called from King James I of England, in whose reign it was struck. See Coin.

We usually distinguish two kinds of Jacobus, the old and the new; the former valued at 25 shillings, weighing six penny-weights ten grains; the latter, called also Carolus, valued at 23 shillings, in weight five penny-weights twenty grains.

JAQUINIA, a genus of plants belonging to the hexandra class, and in the natural method ranking with those of which the order is doubtful. See Botany Index.