Indian Ocean
a body of water bounded on the W. by Africa, on the N. by Asia, on the E. by Australia and the Australasian Islands. According to modern geographers it is limited to the S. by the 40th parallel of S. latitude, in which region it opens widely into the Southern and Antarctic oceans. It gradually narrows towards the N., and is divided by the Indian peninsula into the Bay of Bengal on the E. and the Arabian Sea on the W., the latter sending N. two arms, the Persian Gulf and the Red Sea.
Within these limits the Indian Ocean is estimated to have an area of 17,320,500 square miles.
At the dawn of history the Indian Ocean was known as the Erythræan Sea.
Necho, an Egyptian monarch who flourished about 610 в. c., is reported by Herodotus to have sent some of his vessels, manned by Phoenicians, into the Erythræan Sea with orders to return by the S. of Africa and the Pillars of Hercules.
From a very early date there was a coasting trade between India and the Persian Gulf, but the voyage of Nearchus, one of Alexander's generals, from the Indus to the Persian Gulf, is the earliest reliable record of these coasts.
In 1486 the Portuguese rounded the Cape of Good Hope, and in 1498 Vasco da Gama reached the coasts of India by the same route. In 1521 the one remaining ship of Magellan's squadron crossed the INDIAN RED Southern Indian Ocean in completing the first circumnavigation of the world.
The mean depth of the Indian Ocean is estimated at about 2,300 fathoms, or slightly greater than that of the Atlantic.
The area of land draining into the Indian Ocean is estimated at 6,813,600 square miles, and the annual rainfall on this land is equal to 4,379 cubic miles of water. The rivers flowing from the Asiatic continent are by far the most important, and they carry an immense amount of detrital matter into the Bay of Bengal and Arabian Sea, these forming extensive deposits of blue mud. The temperature of the surface waters of the Indian Ocean varies much in different parts of the ocean, and at the same place at different times of the year or states of the wind . In tropical regions the temperature usually varies from 70° to 80° F., and the yearly range is only 7° or 8° F.
The temperature of the water at the bottom of the Indian Ocean is very uniform and subject to little, if any, annual variation. In the Bay of Bengal and Arabian Sea temperatures of 33.7° F. 34.2° F. have been recorded at the bottom.
The currents of the Indian Ocean are less constant than in the other great oceans, and are largely controlled by the direction and strength of the monsoons.
Some of the most characteristic coral atolls and islands are to be found toward the central part of the Indian Ocean, such as the great Maldive group, the Chagos, Diego Garcia, and the Cocos Islands. Christmas Island is an upraised coral formation. St. Paul's, Mauritius, Rodriguez, and others are of volcanic origin, while Madagascar, Ceylon, and Socotra are typical continental islands. INDIAN TERRITORY Arizona Acres Navaho .12.115,283 Fort Apache 1,681,920 Hopi 2,472,230 San Carlos. 1,834,240 Minnesota Red Lake Oklahoma Acres Choctaw 2,590,045 Wichita ... 1,511,576 Chickasaw 803,108 Oregon Klamath 872,186 .. 543,528 South Dakota Cheyenne Montana River 2,467,926 1,836,753 1,774,967 Pine Ridge. 1,943,121 Rosebud 1,524,210 959,644 California Mission (28 reserves) 202,216 474,240 315,040 Colorado Fort Hall .. 447,940 Crow Fort Peck Blackfeet Mescalero Apache Zuñi ..
New Mexico North Dakota Standing Rock ... 1,847,812 Washington Colville Yakima ... 1,297,009 837,758 reservations in the United States was in The total acreage given over to Indian 1920, 48,477,216 acres.