LAKANAL, Joseph, French statesman : b. Serres, 14 July 1762; d. Paris, 14 Feb. 1845. He was educated by the Doc trinaires, joined their congregation and became a teacher, then professor In philosophy at Moulins. In 1791 his uncle Font made him vicar-general at Ariege, and he was sent to the National Convention (1792) as deputy for his department. There he voted for the uncondi tional death of Louis XVI. He soon rose to the presidency of the committee of public in struction; he had the Jardin du Roi reorgan ized and called the Museum of Natural His tory. He took a prominent part in the creation of the P..cole Normale, Institute, central schools, primary schools and in adopting atrial telegra phy. He was appointed commissary by the Directory (1795) to assist in several newly annexed French departments. In the same year he presented a plan for the establishment and organization of central schools, and he also entered the Council of 500, but on the 18 Brumaire, he resigned all positions except the chair of the Central School. In 1816 he was banished as a regicide and his name was erased from the list of the Institute he had founded. Emigrating to the United States he became president of University of Louisiana and then an Alabama planter. On the re-establishment of the Academie des Sciences Morales et Politiques (1832) he returned to France to claim his orig inal post, which was given to him in 1834. Con sult Saint-Hilaire, G., 'Lakanal, sa vie et ses travaux' (1849) ; Lavigne, B., 'Joseph Lakanal' (1880).
LAKE (Lat. locus), a standing body of water surrounded by land. Lakes are of two kinds — fresh-water and saline — and have been formed in various ways. Taking first the fresh-water lakes, these may be grouped as follows: (1) Obstruction Lakes.— Some of these are more or less temporary sheets of water, such as the lake-like expansions of cer tain rivers, and the deserted loops of river channels. Other temporary lakes are due to the operations of the beaver; to the choking of the narrower passages of a river-channel by drifted vegetable debris or river-ice; to the advance of a glacier across the mouth of a lateral valley, to the damming of valleys by lava flows or to obstructions by landslides. (2) Crater Lakes.—These occupy the craters of extinct or quiescent volcanoes. (3) Sink Lakes.— These lie in hollows caused by sub sidence of the surface consequent upon the re moval of underlying soluble rocks, such as rock-salt and calcareous and gypseous rocks. (4) Earth-movement Lakes.— Unequal move
ments or warping of the earth's crust have occasionally originated hollows by direct sub sidence. It is possible also that local elevation by affecting the lower ends of valleys may some times have obstructed the flow of rivers and thus given rise to lakes. (5) Glacial Lakes.— These consist of (a) hollows of erosion or rock-basins, which have been excavated by glacier-ice, and (b) hollows caused by the un equal distribution or accumulation of glacial detritus during the glacial period. (6) Subter ranean Lakes.— These are found chiefly in cal careous regions, where they occupy the under ground channels which have been excavated by the chemical and mechanical action of water. Fresh-water lakes are very unequally distributed. They are most numerous in those regions which were overflowed by land-ice during the glacial period, as in the British Islands, Scandinavia, Finland, Canada and the United States. Lakes occur at all heights above the sea; the most elevated being Lake Tsana in Abyssinia (7,500 feet), Lake Titicaca in the Bolivian Andes (12,500 feet) and Askal Chin in Tibet (16,600 feet). The largest lake in the world is Lake Superior, which covers an area of 31,200 square miles, and has a mean depth of about 475 feet. Lake Baikal, in central Asia, is the largest and deepest mountain lake, its area being 11,580 square miles, and in places reaches a depth of 5,400 feet. Some of the mountain lakes of Europe also attain great depths; thus, Lake Geneva is 1,000 feet, Lago Maggiore 1,158 feet and Como 1,358 feet.
Salt Two kinds are recognized: (a) portions of the sea cut off the general oceanic area by epigene or hypogene agencies; (b) lakes, originally fresh-water, which have been rendered saline by evaporation and con centration. Those of the first group range in size from mere pools and lagoons up to inland seas, such as those of the great Aralo-Caspian depression. The Dead Sea and the Great Salt Lake of Utah are good examples of the second group of saline lakes, which might be defined shortly as lakes which have no outlet to the ocean. The Caspian Sea is 97 feet below the level of the Black Sea, has an area of about 170,000 square miles and is from 2,500 to 3,000 feet deep in the deepest parts. A still more de pressed area is that of the Dead Sea, the sur face of which is 1,292 feet below the level of the Mediterranean Sea.
In Scotland the term loch is applied to lakes or lake-like extensions of the sea completely shut in by land.