Australia (older name, New Holland), the largest island in the world, a sea-girt continent, lying between the Indian and Pacific Oceans, S.E. of Asia; between lat. 10° 39' and 39° 11' S.; long. 113° 5' and 153° 16' E.; greatest length, from W. to E., 2400 miles; greatest breadth, from N. to S., 1700 to 1900 miles. It is separated from New Guinea on the north by Torres Strait, from Tasmania on the south by Bass Strait. It is divided into two unequal parts by the Tropic of Capricorn, and consequently belongs partly to the South Temperate, partly to the Torrid Zone. It is occupied by five British colonies, namely, New South Wales, Victoria, and Queensland in the east; South Australia in the middle, stretching from sea to sea; and Western Australia in the west, which, with the Island of Tasmania, form the Commonwealth of Australia. Their area and population are as follows:—

Area in
sq. m. 		Pop. in
1920
New South Wales 309,432 2,091,115
Victoria 87,884 1,528,151
Queensland 670,500 752,245
South Australia 380,070 491,177
Western Australia 975,920 330,819
Tasmania 26,215 212,847
Northern Territory 523,620 3,992
Federal Territory 940 1,972

Sydney, Melbourne, Adelaide, Brisbane, and Perth are the chief towns. The population of the Commonwealth of Australia was 4,895,894 in 1917 and 5,412,318 in 1920.

Although there are numerous spacious harbours on the coasts, there are few remarkable indentations, the principal being the Gulf of Carpentaria, on the N., the Great Australian Bight, and Spencer's Gulf, on the S. The chief projections are Cape York Peninsula and Arnhem Land in the north. Parallel to the N.E. coast runs the Great Barrier Reef for 1000 miles. In great part the E. coast is bold and rocky, and is fringed with many small islands. Part of the S. coast is low and sandy, and part presents cliffs of several hundred feet high. The N. and W. coasts are generally low, with some elevations at intervals.

The interior, so far as explored, is largely composed of rocky tracts and barren plains with little or no water. The whole continent forms an immense plateau, highest in the east, low in the centre, and with a narrow tract of land usually intervening between the elevated area and the sea. The base of the table-land is granite, which forms the surface-rock in a great part of the south-west, and is common in the higher grounds along the east side. Secondary (cretaceous) and tertiary rocks are largely developed in the interior. Silurian rocks occupy a large area in South Australia, on both sides of Spencer Gulf. The mountainous region in the south-east and east is mainly composed of volcanic, Silurian, carbonaceous, and carboniferous rocks yielding good coal. No active volcano is known to exist, but in the south-east there are some craters only recently extinct. The highest and most extensive mountain-system is a belt about 150 miles wide skirting the whole eastern and south-eastern border of the continent, and often called, in whole or in part, the Great Dividing Range, from forming the great water-shed of Australia. A part of it, called the Australian Alps, in the south-east, contains the highest summits in Australia, Mount Kosciusko (7175 feet), Mount

Clarke (7256 feet), and Mount Townshend (7353 feet). West of the Dividing Range are extensive plains or downs admirably adapted for pastoral purposes. The deserts and scrubs, which occupy large areas of the interior, are a characteristic feature of Australia. The former are destitute of vegetation, or are covered only with a coarse, spiny grass that affords no sustenance to cattle or horses; the latter are composed of a dense growth of shrubs and low trees, often impenetrable till the traveller has cleared a track with his axe.

The rivers of Australia are nearly all subject to great irregularities in volume, many of them at one time showing a channel in which there is merely a series of pools, while at another they inundate the whole adjacent country. The chief is the Murray, which, with its affluents the Murrumbidgee, Lachlan, and Darling, drains a great part of the interior west of the Dividing Range, and falls into the sea on the south coast (after entering Lake Alexandrina). Its greatest tributary is the Darling, which may even be regarded as the main stream. On the east coast are the Hunter, Clarence, Brisbane, Fitzroy, and Burdekin; on the west, the Swan, Murchison, Gascoyne, Ashburton, and De Grey; on the north, the Fitzroy, Victoria, Flinders, and Mitchell. The Australian rivers are of little service in facilitating internal communication. Many of them lose themselves in swamps or sandy wastes of the interior. A considerable river of the interior is Cooper's Creek, or the Barcoo, which falls into Lake Eyre, one of a group of lakes on the south side of the continent having no outlet, and accordingly salt. The principal of these are Lakes Eyre, Torrens, and Gairdner, all of which vary in size and saltness according to the season. Another large salt lake of little depth, Lake Amadeus, lies a little west of the centre of Australia. Various others of less magnitude are scattered over the interior.

The climate of Australia is generally hot and dry, but very healthy. In the tropical portions there are heavy rains, and in most of the coast districts there is a sufficiency of moisture, but in the interior the heat and drought are extreme. Considerable portions now devoted to pasturage are liable at times to suffer from drought. At Melbourne the mean temperature is about 56°, at Sydney about 63°. The south-eastern settled districts are at times subject to excessively hot winds from the interior, which cause great discomfort, and are often followed by a violent cold wind from the south ('southerly bursters'). In the mountainous and more temperate parts snow-storms are common in winter (June, July, and August).

Australia is a region containing a vast quantity of mineral wealth. Foremost come its rich and extensive deposits of gold, which, since the precious metal was first discovered in 1851, have produced a total of nearly £600,000,000. The greatest quantity has been obtained in Victoria,