Raphael Semmes, Memoirs of Service Afloat During the War Between the States

If the reader will inspect a map, he will find that the North Indian Ocean is bounded wholly by tropical countries—Hindostan, Beloochistan, and Arabia to the Red Sea, and across that sea, by Azan and Zanguebar. The waters in this great bight of the ocean are intensely heated by the fervor of an Indian and African sun, and flow off in quest of cooler regions through the Mozambique Channel. Passing thence over the Agulhas Bank, which lies a short distance to the eastward of the Cape of Good Hope, they reach that Cape, as the Agulhas current. Here it divides into two main prongs or branches; one prong pursuing a westerly course, and joining in with the great equatorial current, which, the reader recollects, we encountered off Fernando de Noronha, and the other bending sharply to the south-east, and forming the Gulf Stream of the South Indian Ocean, in which the Alabama is at present. What it is, that gives this latter prong its sudden deflection to the southward is not well understood. Probably it is influenced, to some extent, by the southerly current, running at the rate of about a knot an hour along the west coast of Africa, and debouching at the Cape of Good Hope. Here it strikes the Agulhas current at right angles, and hence possibly the deflection of a part of that current.

But if there be a current constantly setting from the Cape of Good Hope to the south-east, how is it that the iceberg finds its way to the neighborhood of that Cape, from the south polar regions? There is but one way to account for it. There must be a counter undercurrent. These bergs, setting deep in the water, are forced by this counter-current against the surface current. This phenomenon has frequently been witnessed in the Arctic seas. Captain Duncan, of the English whaler Dundee, in describing one of his voyages to Davis' Strait, thus speaks of a similar drift of icebergs:—‘It was awful to behold the immense icebergs working their way to the north-east from us, and not one drop of water to be seen; they were working themselves right through the middle of the ice.’ Here was an undercurrent of such force as to carry a mountain of ice, ripping and crashing through a field of solid ice. Lieutenant De Haven, who made a voyage in search of Sir John Franklin, describes a similar phenomenon as follows:—‘The ’