In the tube anemometer also it is really the pressure that is measured, although the scale is usually graduated as a velocity scale. In cases where the density of the air is not of average value, as on a high mountain, or with an exceptionally low barometer for example, an allowance must be made. Approximately 1½% should be added to the velocity recorded by a tube anemometer for each 1000 ft. that it stands above sea-level.

(W. H. Di.)

ANEMONE, or WIND-FLOWER (from the Gr. ἄνεμος, wind), a genus of the buttercup order (Ranunculaceae), containing about ninety species in the north and south temperate zones. Anemone nemorosa, wood anemone, and A. Pulsatilla, Pasque-flower, occur in Britain; the latter is found on chalk downs and limestone pastures in some of the more southern and eastern counties. The plants are perennial herbs with an underground rootstock, and radical, more or less deeply cut, leaves. The elongated flower stem bears one or several, white, red, blue or rarely yellow, flowers; there is an involucre of three leaflets below each flower. The fruits often bear long hairy styles which aid their distribution by the wind. Many of the species are favourite garden plants; among the best known is Anemone coronaria, often called the poppy anemone, a tuberous-rooted plant, with parsley-like divided leaves, and large showy poppy-like blossoms on stalks of from 6 to 9-in. high; the flowers are of various colours, but the principal are scarlet, crimson, blue, purple and white. There are also double-flowered varieties, in which the stamens in the centre are replaced by a tuft of narrow petals. It is an old garden favourite, and of the double forms there are named varieties. They grow best in a loamy soil, enriched with well-rotted manure, which should be dug in below the tubers. These may be planted in October, and for succession in January, the autumn-planted ones being protected by a covering of leaves or short stable litter. They will flower in May and June, and when the leaves have ripened should be taken up into a dry room till planting time. They are easily raised from the seed, and a bed of the single varieties is a valuable addition to a flower-garden, as it affords, in a warm situation, an abundance of handsome and often brilliant spring flowers, almost as early as the snowdrop or crocus. The genus contains many other lively spring-blooming plants, of which A. hortensis and A. fulgens have less divided leaves and splendid rosy-purple or scarlet flowers; they require similar treatment. Another set is represented by A. Pulsatilla, the Pasque-flower, whose violet blossoms have the outer surface hairy; these prefer a calcareous soil. The splendid A. japonica, and its white variety called Honorine Joubert, the latter especially, are amongst the finest of autumn-blooming hardy perennials; they grow well in light soil, and reach 2½ to 3 ft. in height, blooming continually for several weeks. A group of dwarf species, represented by the native British A. nemorosa and A. apennina, are amongst the most beautiful of spring flowers for planting in woods and shady places.

The genus Hepatica is now generally included in anemone as a subgenus. The plants are known in gardens as hepaticas, and are varieties of the common South European A. Hepatica; they are charming spring-flowering plants with usually blue flowers.

ANENCLETUS, or ANACLETUS, second bishop of Rome. About the 4th century he is treated in the catalogues as two persons—Anacletus and Cletus. According to the catalogues he occupied the papal chair for twelve years (c. 77-88).

ANERIO, the name of two brothers, musical composers, very great Roman masters of 16th-century polyphony. Felice, the elder, was born about 1560, studied under G. M. Nanino and succeeded Palestrina in 1594 as composer to the papal chapel. Several masses and motets of his are printed in Proske's Musica Divina and other modern anthologies, and it is hardly too much to say that they are for the most part worthy of Palestrina himself. The date of his death is conjecturally given as 1630. His brother, Giovanni Francesco, was born about 1567, and seems to have died about 1620. The occasional attribution of some of his numerous compositions to his elder brother is a pardonable mistake, if we may judge by the works that have been reprinted. But the statement, which continues to be repeated in standard works of reference, that "he was one of the first of Italians to use the quaver and its subdivisions" is incomprehensible. Quavers were common property in all musical countries quite early in the 16th century, and semiquavers appear in a madrigal of Palestrina published in 1574. The two brothers are probably the latest composers who handled 16th-century music as their mother-language; suffering neither from the temptation to indulge even in such mild neologisms as they might have learnt from the elder brother's master, Nanino, nor from the necessity of preserving their purity of style by a mortified negative asceticism. They wrote pure polyphony because they understood it and loved it, and hence their work lives, as neither the progressive work of their own day nor the reactionary work of their imitators could live. The 12-part Stabat Mater in the seventh volume of Palestrina's complete works has been by some authorities ascribed to Felice Anerio.

ANET, a town of northern France, in the department of Eure-et-Loir, situated between the rivers Eure and Vègre, 10 m. N.E. of Dreux by rail. Pop. (1906) 1324. It possesses the remains of a magnificent castle, built in the middle of the 16th century by Henry II. for Diana of Poitiers. Near it is the plain of Ivry, where Henry IV. defeated the armies of the League in 1590.

ANEURIN, or ANEIRIN, the name of an early 7th-century British (Welsh) bard, who has been taken by Thomas Stephens (1821-1875), the editor and translator of Aneurin's principal epic poem Gododin, for a son of Gildas, the historian. Gododin is an account of the British defeat (603) by the Saxons at Cattraeth (identified by Stephens with Dawstane in Liddesdale), where Aneurin is said to have been taken prisoner; but the poem is very obscure and is differently interpreted. It was translated and edited by W. F. Skene in his Four Ancient Books of Wales (1866), and Stephens' version was published by the Cymmrodorion Society in 1888. See CELT: Literature (Welsh).

ANEURYSM, or ANEURISM (from Gr. ἀνεύρισμα, a dilatation), a cavity or sac which communicates with the interior of an artery and contains blood. The walls of the cavity are formed either of the dilated artery or of the tissues around that vessel. The dilatation of the artery is due to a local weakness, the result of disease or injury. The commonest cause is chronic inflammation of the inner coats of the artery. The breaking of a bottle or glass in the hand is apt to cut through the outermost coat of the artery at the wrist (radial) and thus to cause a local weakening of the tube which is gradually followed by dilatation. Also when an artery is wounded and the wound in the skin and superficial structures heals, the blood may escape in to the tissues, displacing them, and by its pressure causing them to condense and form the sac-wall. The coats of an artery, when diseased, may be torn by a severe strain, the blood escaping into the condensed tissues which thus form the aneurysmal sac.

The division, of aneurysms into two classes, true and false, is unsatisfactory. On the face of it, an aneurysm which is false is not an aneurysm, any more than a false bank-note is legal tender. A better classification is into spontaneous and traumatic. The man who has chronic inflammation of a large artery, the result, for instance, of gout, arduous, straining work, or kidney-disease, and whose artery yields under cardiac pressure, has a spontaneous aneurysm; the barman or window-cleaner who has cut his radial artery, the soldier whose brachial or femoral artery has been bruised by a rifle bullet or grazed by a bayonet, and the boy whose naked foot is pierced by a sharp nail, are apt to be the subjects of traumatic aneurysm. In those aneurysms which are a saccular bulging on one side of the artery the blood may be induced to coagulate, or may of itself deposit layer upon layer of pale clot, until the sac is obliterated. This laminar coagulation by constant additions gradually fills the aneurysmal cavity and the pulsation in the sac then ceases; contraction of the sac and its contents gradually takes place and the aneurysm is cured. But in those aneurysms which are fusiform dilatations of the vessel there is but slight chance of such cure, for the blood sweeps evenly through it without staying to deposit clot or laminated fibrine.