Page:Physical Geography of the Sea and its Meteorology.djvu/76

50 bique current, which runs south along the east coast of Africa from the Indian Ocean, and with the cooler current setting to the north on the Australian side of the same sea. Between these there is a sargasso on the left; for it is in the southern hemisphere. 138. Their position conforms to the theory.—Again, there is in the South Pacific a flow of equatorial waters to the Antarctic on the east of Australia, and of Antarctic waters (Humboldt's current) to the north, along the western shores of South America; and, according to this principle, there ought to be another sargasso somewhere between New Zealand and the coast of Chili. (See Plate IX.) 139. The discovery of a new sargasso.—To test the correctness of this view, I requested Lieut. Warley to overhaul our sea-journals for notices of kelp and drift matter on the passage from Australia to Cape Horn and the Chincha Islands. He did so, and found it abounding in small patches, with "many birds about," between the parallels of 40° and 60° south, the meridians of 140° and 178° west. This sargasso is directly south of the Georgian Islands, and is, perhaps, less abundantly supplied with drift matter, less distinct in outline, and less permanent in position than any one of the others.

140. One in the South Atlantic.—There is no warm current, or if one, a very feeble one, flowing out of the South Atlantic. Most of the drift matter borne upon the ice-bearing current into that sea finds its way to the equator, and then into the veins which give volume to the Gulf Stream, and supply the sargasso of the North Atlantic with extra quantities of drift. The sargassos of the South Atlantic are therefore small. The formations and physical relations of sargassos will be again alluded to in Chapter XVIII.

141. The large volume of warm water outside of the Gulf Stream.—Let us return (§ 129) to this great expanse of warm water which, coming from the torrid zone on the south-western side of the Atlantic, drifts along to the north on the outside of the Gulf Stream. Its velocity is slow, not sufficient to give it the name of current; it is a drift, or what sailors call a "set." By the time this water reaches a parallel of 35° or 40° it has parted with a good deal of its intertropical heat: consequent upon this change in temperature is a change in specific gravity also, and by reason of this change, as well as by the difficulties of crossing