ALGORISM, a name applied in the middle ages to arithmetic employing the Indo-Arabic numerals. (See ALGEBRA for Moham med ibn Musa al-Khowarizmi, who wrote Liber Algorism, "the Book of al-Khowarizmi.") It appeared in mediaeval French as augrisme and augrime, and was thence carried to England as augrym or augrim, as in Chaucer's Astrolabe, his Testament of Love and his Clerk's Tale. In Spanish it takes such forms as al guarisma. In the middle ages the abacists computed on the abacus (q.v.), while the algorists computed by algorism. Robert Recorde (q.v.) wrote in his Ground of Artes (c. 1542) : "Some call it Arsemetrick, and some Augrime. . . . Both names are cor ruptly written : Arsemetrick for Arithmetick, as the Greeks call it, and Augrime for Algorisme, as the Arabians found it" (1646 edition). Early European writers thought that the word came from Algus, a king of India; thus in a manuscript of c. 1300: "Ther was a kyng of Inde the quich heyth Algor, he made this craft. And aft his name he called hit algory."