THE INDIAN OCEAN BOUNDARIES AND EXTENT The Indian Ocean is distinguished from the Atlantic and Pacific Oceans by not only a much smaller area, but also by the fact that it alone of the three great oceans is entirely separated from the North Polar Basin. Both the Atlantic and Pacific communicate with the Arctic Ocean—the former freely by two large channels; the latter by the narrow strait of Behring. But between the Indian Ocean and the Arctic Sea there intervenes the vast continent of Asia, stretching south, meeting the northern limits of the waters of this ocean only twenty degrees north of the equator. Unlike the North Atlantic and North Pacific, the North Indian Ocean is re stricted in area, and, consequently, the vast thermal currents and other physical features that distinguish the other oceans north of the equator are wanting. South of the equator, however, the Indian Ocean, like the Atlantic and Pacific, opens out broadly into the unknown ice-bound expanse within the Antarctic Circle. Bounded on the north by Asia, on the west by Africa, and on the east by Malaysia and Australia, its limits on the south are partly natural—such as Clarie, Sabrina, Kemp, and Enderby, Lands—and partly imaginary, along the Antarctic Circle. South of Cape Agulhas, the south ernmost point of the African continent, the boundary between the Indian and Atlantic Oceans is an imaginary line drawn from that cape along the meridian of 20° E. long. to the
Antarctic Circle. Similarly, the boundary on the east, south of Tasmania, is also theoretical, the meridian of South-West Cape in that island being taken as the limit between the Indian and Pacific Oceans. The meridional distance from the coast of Beloochistan, on the north, to Kemp Land, on the south, is about 6,300 miles ; under the equator this ocean extends uninterruptedly for nearly 4,000 miles, and further south, between Shark Bay on the east, and Delagoa Bay on the west, more than 5,000 miles. Still further south we have an extreme breadth of upwards of 6,000 miles from Cape Agulhas to Tasmania. Its area has been variously estimated at from 17,000,000 to 25,000,000 square miles ; one eminent geographer estimates it at 29,219,000 square miles. If we take 'a line from Cape Agulhas to Cape Leeuwin as the southern boundary of the Indian Ocean, its shape might be described in general terms as approximating to an equilateral triangle ; its apex being intersected by the great, wedge-like promontory of Hindostan, the western coasts of which are opposite to those of Arabia; its eastern shores being opposite to those of Further India. South of the parallel of 10° N. lat. we have—