THE INDIAN OCEAN GENERAL CHARACTER OF COASTS PRINCIPAL CURRENTS DEPTH AND FORM OF ITS BASIN From Algoa Bay to Natal the coast is comparatively high, and in parts rocky and entirely destitute of harbours. The ports of Elizabeth and East London are open, exposed bays; while that of Natal is rendered almost useless, except to small vessels, by a dangerous bar right across its entrance. Thence to the magnificent natural harbour of Delagoa Bay the coast is low, and generally fertile. From this inlet to Zanzibar the coast is generally low, swampy in some parts, and extremely fertile in others ; but further north, to Cape Guardafui, extends a strip of wild and desert coast. The coast of the Red Sea presents " nothing but precipitous gulleys, barren sands, and inaccessible cliffs." The northern shores of the Indian Ocean are indented by the three peninsulas of Arabia, India, and Malaysia, and contain several good ports. The eastern shores of the Red Sea are rugged and inaccessible, and those of the Arabian Sea are generally precipitous. The navigation of the Persian Gulf is rendered difficult by numer ous coral reefs and islets. South of the Gulfs of Cutch and Cambay, the Malabar coast of India has but few good har bours, that of Bombay being the best. The eastern, or Coromandel coast, is generally low and unbroken, has no harbours, and is exposed to heavy surf; vessels lying off Madras and other towns on the coast anchor in open road steads. The northern coasts of Australia are generally low, and not unfertile in some parts. Besides the large inlet called the Gulf of Carpentaria, there are several other smaller bays, which form good natural harbours. From Shark Bay to Bing George's Sound the coast is somewhat higher, and in parts rocky. Thence eastwards the shores of the great Australian Bight are low, sandy, and barren, except here and there, between Spencer Gulf and Cape Wilson. Both on the south coast of Australia and the island of Tasmania are several inlets, which form excellent harbours.
The currents of the Indian Ocean are not so nume rous or persistent as those of the larger Pacific and Atlantic Oceans. Being entirely land-locked on the north, and ex tending scarcely twenty degrees north of the equator, there is no room for the development of such grand currents as the Gulf Stream of the North Atlantic and the Black Stream of the North Pacific. This ocean is, moreover, subject to severe periodical and variable winds. The periodical winds are known as the monsoons, and blow from the north-east for half the year, and from the south-west during the other half.'
Farther north, in the Arabian Sea and Bay of Bengal, the winds vary their direction according to the position and con tour of the regions over which they blow. In the Red Sea the winds "follow the direction of its shores, and blow, for six months of the year, alternately up and down its long trough-like valley, confined and guided in their passage by the mountain chains which bound it upon either side." Evapora tion is also most especially in the Red Sea ; and pre cipitation along the southern slopes of the Himalaya is enor mous." All these causes—variable and periodical winds, active evaporation and heavy precipitation, and consequent discharge of immense volumes of water by the Ganges, Indus, and other livers—combine to make the current-system of the North Indian Ocean most complicated and uncertain.
South of the equator the case is different. There we have not only a comparatively large area for development, but also an almost uninterrupted communication with .the South Polar basin, whence the great current systems of all the great oceans seem to receive their primary impulse. Between the parallels of 40° and 60° there is a general north-easterly " set " of the chilled and iceberg-laden waters from the Antarctic regions. Striking against the western coasts of all the great continents, it divides ; its branches flowing north along the western shores of Australia, Africa, and South America, and ultimately merging in the equatorial currents of the Indian, Atlantic, and Pacific Oceans respectively. Off the eastern extremities of the three continents, this Antarctic Drift, as it is called, is encountered by warm currents from the equatorial regions of the great oceans—the Agulhas current off South Africa, the Brazilian current off Patagonia, and the East Australian current off Victoria. The low temperature of the Antarctic Drift current is undoubtedly due to its origin, and the continual supply of icy-cold water by the constant lique faction of enormous icebergs, vast numbers of which float in the Southern Ocean, between 60° and 40° south latitude. In all cases the encounter between this cold north-easterly drift and the southerly warm currents from the equator results in the total or nearly entire deflection of the latter to the eaat ward ; that is, excepting those portions which sink and travel in a south-easterly direction towards the South Polar regions as warm under-currents.