AILSA CRAIG, a remarkable island-rock at the mouth of the Firth of Clyde, off the coast of Ayrshire, Scotland. It is of a conoidal form, with an irregular elliptic base, and rises abruptly from the sea to the height of 1139 feet. The only side from which the rock can be ascended is the east; the other sides being for the most part perpendicular, and generally presenting lofty columnar forms, though not so regular as those of Staffa. The rock is a grecnstone or sycnite, with a basis of grayish compact felspar traversed by numerous trap veins. A columnar cave exists towards the north side, and on the eastern are the remains of a tower, with several vaulted rooms. Two springs occur on the island, and some scanty grass affords subsistence to numerous rabbits. The precipitous parts of the rock are frequented by large flocks of solan geese and other aquatic wild fowl. It is situated in 55° 15' N. lat., 5° 7' W. long.

AIN, a department on the eastern frontier of France, bounded on the N. by the departments of Jura and Saoneet-Loire, on the W. by Sa8ne-et-Loire and Rhone, on the S. by Isere, and on the E. by the departments of Savoie and Haute Savoie and the Swiss cantons Geneva and Vaud. It extends at the widest points 52 miles from N. to S., and about the same distance from E. to W., with an area of 2241 square miles. The east of the department is very mountainous, being traversed by the southern portion of the Jura range, but in the north-west the surface is comparatively level, and in the south-wcst flat and marshy. Ain is wholly within the basin of the RhOne, that river itself being the boundary on the east and south, while it receives the Ain, which passes southward through the centre, and the Saone, which forms the western boundary of the department. The climate is usually cold, but on the whole healthy, except in the damp marshy districts on the west. The soil in the valleys and plains of the department is fertile, producing wheat, barley, maize, rye, and fruits of various kinds, as well as wine of excellent quality; the tops of many of the mountains are covered with forests of fir and oak, and the lower slopes yield excellent pasture for sheep and cattle. The chief mineral product is asphalt, besides which potter's clay, iron, building-stone, and the best lithographic stone in France, are produced in the department. There are many corn and saw mills on the mountain streams; and cotton, linen, and silk fabrics, coarse woollen cloth, paper, and clocks, are manufactured to a limited extent. Ain, which formed a part of the ancient province of Burgundy, is divided into five arrondissements - Bourg and Trevoux in the west, and Gex, Nantua, and Belley in the east; containing in all 36 cantons and 452 communes. Bourg is the capital, and Belley is the seat of a bishop. Population of Ain in 1872, 363,290, of whom 185,074 were males, and 178,216 were females. Of the total population, 115,407 could neither read nor write, and 46,450 more could not write.