is 220. Amicable numbers were known to the Pythagoreans, who accredited them with many mystical properties. A general formula by which these numbers could be derived was invented by the Arabian astronomer Tobit ben Korra (836–901): if p = 3·2m − 1, q = 3·2m−1 − 1 and r = 9·22m−1 − 1, where m is an integer and p, q, r prime numbers, then 2m pq and 2m r are a pair of amicable numbers. This formula gives the pairs 220 and 284, 17,296 and 18,416, 9,463,584 and 9,437,056. The pair 6232 and 6368 are amicable, but they cannot be derived from this formula. Amicable numbers have been studied by Al Madshritti (d. 1007), René Descartes, to whom the formula of Tobit ben Korra is sometimes ascribed, C. Rudolphus and others.
AMICE (earlier forms: amyt, amys, O. Fr. amit, Lat. amictus, from amicire, to throw or wrap round, the change of t to s being probably due to an early confusion with the aumuce: see Almuce), a liturgical vestment of the Western Church. It is a rectangular piece of cloth which is wrapped round the neck, shoulders and breast. Sometimes, more particularly in Germany, 
From Braun, Liturgische Gewandung, by permission
of the publisher, B. Herder.
Fig. 1.—Amice of the Present Day.it is called the humerale (from humerus, shoulder). According to modern Roman use, laid down by the decree of the Congregation of Rites in 1819, the amice must be of linen or of a hempen material, not wool; and, as directed by the new Roman Missal (1570), a small cross must be sewn or embroidered in the middle of it. In putting it on it is first laid on the head, then allowed to fall on the shoulders, and finally folded round the chest and tied with the strings attached for that purpose (see fig. 1).
The amice is now worn under the alb, except at Milan and Lyons, where it is put on over it. The vestment was at first a perfectly plain white cloth, but in the 12th century the custom arose of decorating the upper border with a band of embroidery, the parure (parura) or “apparel.” This was abandoned at Rome about the end of the 15th century and is not prescribed in the Missal; it survived, however, in many parts of Europe till much later. This apparel, when the vestment has been adjusted, forms a sort of stiff collar which appears above the chasuble or dalmatic (see fig. 2). In some exceptional cases, as at Milan, it has become detached from the amice and is fixed like a collar to the chasuble.
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Redrawn from Braun, Liturgische Gewandung. Fig. 2.—Medieval Method of putting on the Amice. |
The Latin word amictus was applied to any wrap-like garment, and, according to Father Braun, the liturgical amice originated in the ordinary neck-cloth worn by all classes of Romans. It had at the outset no liturgical significance whatever, and was simply adopted by the clergy for the same reason that the clergy of the 18th century wore wigs—because it was part of the full dress of ordinary life. The first record of its ecclesiastical use is at Rome in the 8th century, when it was worn only with the dalmatic and was known as the anabolagium (anagolaium, anagolagium, from Gr. ἀναβὀλαιον), a name it continued to bear at Rome till the 13th century. 
From Braun, Liturgische Gewandung.
Fig. 3.—The Papal Fanone.In the 9th century it spread to the other countries that adopted the Roman use: it is mentioned in an inventory of vestments given by Abbot Angilbert (d. 814) to the monastery at Centula (St Riguier) and in the de clericorum institutione of Hrabanus Maurus (c. 820). The amice was worn first simply as a shoulder-cloth, but at the end of the 9th century the custom grew up of putting it on over the head and of wearing it as a hood, either while the other vestments were being put on or, according to the various uses of local churches, during part of the Mass, though never during the canon. This ceased at Rome at the same time as the apparel disappeared; but two relics of it survive—(1) in the directions of the Missal for putting on the amice, (2) in the ordination of subdeacons, when the bishop lays the vestment on the ordinand's head with the words, “Take the amice, which symbolizes discipline over the tongue, &c.” The priest too in putting it on prays, “Place on my head the helmet of salvation, &c.”
The amice, whatever its origin or symbolism, became specifically a vestment associated with the sacrifice of the Mass, and as such it was rejected with the other “Mass vestments” in England at the Reformation. Its use has, however, been revived in many Anglican churches, the favourite form being the medieval apparelled amice. (See Vestments.) A vestment akin to the amice is also worn in the Armenian and some other oriental churches, but it is unknown to the Orthodox Eastern Church.
Akin to the amice is a vestment peculiar to the popes, the fanone (Med. Lat. fano, “cloth,” Goth. fana, “cloth,” Mod. Ger. Fahne, “a flag”), also called the orale (from ora, an edge, border). This is at present a circular broad collar of two thicknesses of silk, ornamented with gold stripes and a gold-embroidered cross (see fig. 3). It is put on after the alb, &c., and under the tunicle, dalmatic and chasuble, but then drawn up so as to fall over the latter like a collar. The fanone was originally a cloth like the amice and was wrapped round neck and shoulders; until the 15th century, moreover, it was not worn with the amice. Since then, however, both vestments have been worn, one under, the other over, the alb. It is worn by the popes only on certain special days or occasions, and forms part of the vestments in which they are buried.
See Joseph Braun, S. J., Die liturgische Gewandung, pp. 21-56 (Freiburg im Breisgau, 1907), and bibliography to the article Vestments.
AMICI, GIOVANNI BATTISTA (1786–1863), Italian astronomer and microscopist, was born on the 25th of March 1786 at Modena. After studying at Bologna, he became professor of mathematics at Modena, and in 1831 was appointed inspector-general of studies in the duchy. A few years later he was chosen director of the observatory at Florence, where he also lectured at the museum of natural history. He died at Florence on the 10th of April 1863. His name is best known for the improvements he effected in the mirrors of reflecting telescopes and especially in the construction of the microscope. He was also a diligent and skilful observer, and busied himself not only with astronomical subjects, such as the double stars, the satellites of Jupiter and the measurement of the polar and equatorial diameters of the sun, but also with biological studies of the circulation of the sap in plants, the fructification of plants, infusoria, &c.
AMICIS, EDMONDO DE (1846–1908), Italian writer, was born at Oneglia, in Liguria, on the 21st of October 1846. After some schooling at Cuneo and Turin, he was sent to the Military School at Modena, from which he was appointed to a lieutenancy in the 3rd regiment of the line in 1865. He fought at the battle of Custozza in 1866. In 1867 he became director of the Italia
