BAIKAL (i.e., Baïakhal, or Abundant Water), a great fresh-water lake of Siberia, in the government of Irkutsk, 397 miles in length from S.W. to N.E., and from 13 to 54 miles in breadth, with an area of about 12,500 square miles. This vast reservoir is situated 1360 feet above the level of the sea, in the midst of steep mountain ranges, that often rise sheer from the water s edge in lofty walls of syenite, gneiss, or conglomerate, while elsewhere their sloping flanks are thickly clad with dark forests of conifer ous trees. The lake is fed by several rivers, the Upper Angara, the Selenga, which descends from the basin of Lake Kossogol, the Barguzin, and others ; while the only visible outlet is by the Lower Angara, a tributary of the Yenisei The water is excellent, and is extremely clear, so that the bottom can be seen at the depth of 8 fathoms. The depth of the lake varies from 22 to upwards of 300 fathoms. It yields abundance of salmon, and there is a profitable fishery of seals on its shores during the whole summer. The climate is extremely severe ; and the lake, which is frozen over from November to May, is almost perpetually swept by the wind. It facilitates, however, the Russian trade with China, and that between Irkutsk and Dauria. It is navigated by the Russians in summer, and in winter they cross it on the ice. Europeans em barked on its waters for the first time in 1643. Steam- vessels were introduced in 1846, and the passage across is made in about eight hours. Several hot springs and mineral waters are seen on the margin, and naphtha is sometimes found floating on the surface. The lake is between 51 20 and 55 30 N. lat., and 103 and 110 E. long. The island of Olkhon, near its north shore, is 32 miles long and nearly 10 broad. This island and the southern borders of the lake are inhabited by Mongolian tribes, while towards the north the Tungooses are to be found in gradually diminishing numbers. (See " Description du lac de Baikal," trad, du russe par M. Klaproth, in Nouv. Ann. des Voy. t. xvii. p. 289; Ermsm s Siberia, 1848 ; Semenoff, Slovar Ross. Imp.)