KERGUELEN or DESOLATION ISLAND or LAND, an island in the Southern Ocean, to the S.E. of the Cape of Good Hope, and S.W. of Australia, about 2,000 m. S.E. of Madagascar. Kerguelen lies between 39' and 44' S. and 68° 42' and 70° 35' E. Its extreme length is about 85 m., but the area is only about 1,400 sq.m. The island is throughout mountainous, pre senting from the sea in some directions the appearance of a series of jagged peaks. The various ridges and mountain masses are separated by steep-sided valleys, which run down to the sea, forming deep fjords, so that no part of the interior is more than 12 m. from the sea. The chief summits are Mounts Ross (6,12o ft.), Richards (4,000), Crozier (3,251), Wyville Thomson Hooker (2,600), Moseley (2,400). The coast-line is extremely irregular, and the fjords, at least on the north, east and south, form a series of well-sheltered harbours. As the prevailing winds are westerly, the safest anchorage is on the north-east. Christmas Harbour on the north and Royal Sound on the south are noble harbours, the latter with a labyrinth of islets interspersed over upwards of 20 m. of land-locked waters. The scenery is generally magnificent. A district of considerable extent in the centre of the island is occupied by snowfields, whence glaciers descend east and west to the sea. The whole island, exclusive of the snowfields, abounds in freshwater lakes and pools in the hills and lower ground. Hidden deep mud holes are frequent.
Kerguelen Island is of undoubted volcanic origin, the prevailing rock being basaltic lavas, intersected occasionally by dykes, and an active volcano and hot springs are said to exist in the south west of the island. Judging from the abundant fossil remains of trees, the island must have been thickly clothed with woods and other vegetation, of which it has no doubt been denuded by volcanic action and submergence, and possibly by changes of cli mate. It presents evidences of having been subjected to powerful glaciation. The soundings made by the "Challenger" and "Gazelle" and the affinities which in certain respects exist between the islands, seem to point to the existence at one time of an exten sive land area in this quarter, of which Kerguelen, Prince Ed ward's Islands, the Crozets, St. Paul and Amsterdam are the remains. The Kerguelen plateau rises in many parts to within 1,500 fathoms of the surface of the sea. Beds of coal and of red earth are found in some places. The summits of the flat-topped hills about Betsy Cove, in the south-east of the island, are formed of caps of basalt.
According to Sir J. D. Hooker the vegetation of Kerguelen Island is of great antiquity and may have originally reached it from the American continent; it has no affinities with Africa. The present climate is not favourable to permanent vegetation ; the island lies within the belt of rain at all seasons of the year, and is reached by no drying winds; its temperature is kept down by the surrounding vast expanse of sea, and it lies within the line of the cold Antarctic drift. The temperature, however, is equable. The mean annual temperature is about 39° F, while the summer tem perature has been observed to approach Tempests and squalls are frequent, and the weather is rarely calm. On the lower slopes of the mountains a rank vegetation exists, which, from the condi tions mentioned, is constantly saturated with moisture. Several of the marine and many species of freshwater algae are peculiar to the island. The characteristic feature of the vegetation, the Kerguelen's Land cabbage, was formerly abundant, but has been greatly reduced by rabbits introduced to the island. Penguins and sea birds of various kinds are abundant ; a teal (Querque dula Eatoni) peculiar to Kerguelen and the Crozets is also found in considerable numbers. There is a considerable variety of in sects, many of them with remarkable peculiarities of structure, and with a predominance of forms incapable of flying.
The island was discovered by the French navigator, Yves Joseph de Kerguelen-Tremarec, a Breton noble on the 13th of February 1772, and partly surveyed by him in the following year. He was one of those explorers who had been attracted by the belief in a rich southern land, and this island, the South France of his first discovery, was afterwards called by him Desolation Land in his disappointment. Captain Cook visited the island in 1776, and, among other expeditions, the "Challenger" spent some time here. It was occupied in 1874-75 by the expeditions sent to observe the transit of Venus. Projects for more permanent settlement have frequently been brought forward. In Jan. 1893 Kerguelen was annexed by France, and its commercial exploitation was assigned to a private company.
See Y. J. de Kerguelen-Tremarec, Relation de deux voyages dans les mers australes (Paris, 1782) ; Narratives of the Voyages of Captain Cook and the "Challenger" Expedition ; Phil. Trans., vol. 168, con taining account of the collections made in Kerguelen by the British transit of Venus expedition in 1874-75 ; Lieutard, "Mission aux Iles Kerguelen," etc., Annales hydrographiques (Paris, 1893).