This page has been validated.
  
AIR—AIR ENGINE
443

Berbers with negro characteristics. The sultan of Air is to a great extent dependent on the chiefs of the Tuareg tribes inhabiting a vast tract of the Sahara to the north-west. A large part of his revenue is derived from tribute exacted from the salt caravans. Since 1890 Air has been included in the French sphere of influence in West Africa.

Agades, the capital of the country, which has a circuit of 31/2 m., is built on the edge of a plateau 2500 ft. high, and is supposed to have been founded by the Berbers to serve as a secure magazine for their extensive trade with the Songhoi empire. The language of the people is a dialect of Songhoi. In former times Agades was a place of great traffic, and had a population of about 50,000. Since the beginning of the 16th century the prosperity of the town has, however, gradually declined. F. Foureau, who visited Agades in 1899, stated that more than half the total area was deserted and ruinous. The houses, which are built of clay, are low and flat-roofed; and the only buildings of importance are the chief mosque, which is surmounted by a tower 95 ft. high, and the sultan’s residence, a massive two-storied structure pierced with small windows. The chief trade is grain. The great salt caravans pass through it, as well as pilgrims on their way to Mecca.

AIR (from an Indo-European root meaning “breathe,” “blow”), the atmosphere that surrounds the earth; Gr. ἀήρ, the lower thick air, being distinguished from αἰθήρ, the upper pure air. With the development of analytical and especially of pneumatic chemistry, the air was recognized not to be one homogeneous substance, as was long supposed, and different “airs,” or gases, came to be distinguished. Thus oxygen gas, at the end of the 18th century, was known as dephlogisticated air, nitrogen or azote as phlogisticated air, hydrogen as inflammable air, carbonic acid gas as fixed air. The name is now ordinarily restricted to what is more accurately called atmospheric air—the air we breathe—the invisible elastic fluid which surrounds the earth (see Atmosphere). Probably the sense of atmosphere or environment led (though this is disputed by etymologists) to the further use of the word “air” to mean “manner” or “appearance”; and so to its employment (cf. Lat. modus) in music for “melody.” (See Aria.)

AIRAY, HENRY (1560?–1616), English Puritan divine, was born at Kentmere, Westmorland, but no record remains of the date of either birth or baptism. He was the son of William Airay, the favourite servant of Bernard Gilpin, “the apostle of the North,” whose bounty showed itself in sending Henry and his brother Evan (or Ewan) to his own endowed school, where they were educated “in grammatical learning,” and were in attendance at Oxford when Gilpin died. From Wood’s Athenae we glean the details of Airay’s college attendance. “He was sent to St Edmund’s hall in 1579, aged nineteen or thereabouts. Soon after he was translated to Queen’s College, where he became pauper puer serviens; that is, a poor serving child that waits on the fellows in the common hall at meals, and in their chambers, and does other servile work about the college.” His transference to Queen’s is perhaps explained by its having been Gilpin’s college, and by his Westmorland origin giving him a claim on Eaglesfield’s foundation. He graduated B.A. on the 19th of June 1583, M.A. on the 15th of June 1586, B.D. in 1594 and D.D. on the 17th of June 1600—all in Queen’s College. “About the time he was master” (1586) “he entered holy orders, and became frequent and zealous preacher in the university.” His Commentary on the Epistle to the Philippians (1618, reprinted 1864) is a specimen of his preaching before his college, and of his fiery denunciation of popery and his fearless enunciation of that Calvinism which Oxford in common with all England then prized. In 1598 he was chosen provost of his college, and in 1606 was vice-chancellor of the university. In the discharge of his vice-chancellor’s duties he came into conflict with Laud, who even thus early was manifesting his antagonism to the prevailing Puritanism.

He was also rector of Otmore (or Otmoor), near Oxford, a living which involved him in a trying but successful litigation, whereof later incumbents reaped the benefit. He died on the 6th of October 1616. His character as a man, preacher, divine, and as an important ruler in the university, will be found portrayed in the Epistle by John Potter, prefixed to the Commentary. He must have been a fine specimen of the more cultured Puritans—possessed of a robust common-sense in admirable contrast with some of his contemporaries.

AIRD, THOMAS (1802–1876), Scottish poet, was born at Bowden, Roxburghshire, on the 28th of August 1802. He was educated at Edinburgh University, where he made the acquaintance of Carlyle and James Hogg, and he decided to devote himself to literary work. He published Martzoufle, a Tragedy, with other Poems (1826), a volume of essays, and a long narrative poem in several cantos, The Captive of Fez (1830). For a year he edited the Edinburgh Weekly Journal, and for twenty-eight years the Dumfriesshire and Galloway Herald. In 1848 he published a collected edition of his poems, which met with much favour. Carlyle said that he found in them “a healthy breath as of mountain breezes.” Among Aird’s other friends were De Quincey, Lockhart, Stanley (afterwards dean of Westminster) and Motherwell. He died at Dumfries on the 25th of April 1876.

AIRDRIE, a municipal and police burgh of Lanarkshire, Scotland. Pop. (1901) 22,228. It is situated 11 m. E. of Glasgow by the North British railway, and also communicates with Glasgow by the Monkland Canal (which passes within 1 m. of the town), as well as by the Caledonian railway via Coatbridge and Whifflet. The canal was constructed between 1761 and 1790, and connects with the Forth and Clyde Canal near Maryhill. Airdrie was a market town in 1695, but owes its prosperity to the great coal and iron beds in its vicinity. Other industries include iron and brass foundries, engineering, manufactures of woollens and calicoes, silk-weaving, paper-making, oil and fireclay. The public buildings comprise the town hall, county buildings, mechanics’ institute, academy, two fever hospitals and free library, the burgh having been the first town in Scotland to adopt the Free Library Act. Airdrie unites with, Falkirk, Hamilton, Lanark and Linlithgow in sending one member to parliament. The parish of New Monkland, in which Airdrie lies, was formed (with Old Monkland)in 1640 out of the ancient barony of Monkland, so named from the fact that it was part of the lands granted by Malcolm IV. to the monks of Newbattle.

AIRE, a town of south-western France, in the department of Landes, on the left bank of the Adour, 22 m. S.E. of Mont-de-Marsan on the Southern railway between Morcenx and Tarbes. Pop. (1906) 2283. It is the seat of a bishopric, and has a cathedral of the 12th century and an episcopal palace of the 11th, 17th and 18th centuries. Both have undergone frequent restoration. They are surpassed in interest by the church of St Quitterie in Mas d’Aire, the suburb south-west of the town. The latter is a brick building of the 13th and 14th centuries, with a choir in the Romanesque style, and a fine western portal which has been much disfigured. The crypt contains several Gallo-Roman tombs and the sarcophagus (5th century) of St Quitterie. Aire has two ecclesiastical seminaries.

Aire (Atura, Vicus Julii) was the residence of the kings of the Visigoths, one of whom, Alaric II. (q.v.), there drew up his famous code. The bishopric dates from the 5th century.

AIRE, a town of northern France, on the river Lys, in the department of Pas-de-Calais, 12 m. S.S.E. of St Omer by rail. Pop. (1906) 4258. The town lies in a low and marshy situation at the junction of three canals. The chief buildings are the church of St Pierre (15th and 16th centuries), which has an imposing tower and rich interior decoration; a hôtel de ville of the 18th century; and the Bailliage (16th century), a small building in the Renaissance style. Aire has flour-mills, leather and oil works, and nail manufactories, and trade in agricultural produce.

In the middle ages Aire belonged to the counts of Flanders, from whom in 1188 it received a charter, which is still extant. It was given to France by the peace of Utrecht 1713.


AIR-ENGINE, the name given to heat-engines which use air for their working substance, that is to say for the substance which is caused alternately to expand and contract by application