in commerce, a long measure used in China to measure stuffs. Four arsches make three yards of London.

ARENA, a royal or public magazine, or place appointed for the making and keeping of arms, necessary either for defence or assault. Some derive this word from arx, a fortress; others from ars, denoting a machine; others again from arx and senatus, because this was the defence of the senate; but the more probable opinion derives it from the Arabic darsena, which signifies arsenal.

The arsenal of Venice is the place where the galleys are built and laid up. The arsenal of Paris is that where the cannon or great guns are cast.

ARESINIC. See MINERALOGY and CHEMISTRY Index.

ARENIUS, a deacon of the Roman church, of great learning and piety. He was pitched upon by the pope to go to the emperor Theodosius, as tutor to his son Arcadius. Arsenius arrived at Constantinople in the year 383. The emperor happening one day to go into the room where Arsenius was instructing Arcadius, his son was seated, and the preceptor standing; at this he was exceedingly displeased, took from his son the imperial ornaments, made Arsenius sit in his place, and ordered Arcadius for the future to receive his lessons standing uncovered. Arcadius, however, profited but little by his tutor's instructions, for some time after he formed a design of despatching him. The officer to whom Arcadius had applied for this purpose, divulged the affair to Arsenius, who retired to the deserts of Scete, where he passed many years in the exercises of the most strict and fervent devotion. He died there, at 95 years of age.