AMIANTHUS, a name applied to the finer kinds of asbestos (q.v.), in consequence, it is said of the mineral being unaffected by fire (Gr. a/LavTos, undefiled). Some of the finest amianthus, with long silky flexible fibres, occurs in the district of the Taren taise in Savoy. According to Dr. J. W. Evans, the ancient amian thus, derived mostly from Karystos in Euboea and from Cyprus, was probably a fibrous serpentine, or chrysotile (now called locally iratoraK6 r€Tpa, or cotton-stone).
See Mineralogical Mag., vol. xiv. no. 65 (5906), art. by J. W. Evans. AMICABLE NUMBERS (also known as amiable numbers or, less commonly, as agreeable numbers), two integers each of which is equal to the sum of the aliquot parts (q.v.) of the other. For example, 220 and 284 are amicable numbers, for the aliquot parts of 220 are I, 2, 4, 5, Io, II, 20, 22, 44, 55 and I Io, the sum of which numbers is 284. Similarly, the sum of the aliquot parts of 284 (that is, of 1, 2, 4, 71 and 142) is 220. These two numbers are mentioned by the Greek arithmetician, Iamblichus (c. 325). Mathematicians have discovered 63 other pairs.