CUEEEXTS OF THE SEA. 185 



are as clear in favour of this mider current from the Mediterranean 

 as tliey were in favour of the existence of Leverrier's planet before 

 it was seen through the telescope at Berlin. Now suppose, as 

 Sir Charles Lyell maintains, that none of these vast quantities of 

 salt which this smface current takes into the Mediterranean find 

 their way out again. It would not be difficult to show, even to the 

 satisfaction of that eminent geologist, that this indi'aught conveys 

 salt away from the Atlantic faster than all the /?*es/i-water streams 

 empty fresh supplies of salt into the ocean. Now, besides this 

 drain, vast quantities of salts are extracted fi-om sea water for coral 

 reefs, shell banks, and marl beds ; and by such reasoning as this, 

 which is perfectly somid and good, we establish the existence of this 

 under cm-rent, or else we are forced to the very unphilosophical 

 concliLsion that the sea must be losing its salts, and becoming less 

 and less briny. 



390. The Cueeents of the Indian Ocean. — By carefully 

 ctiRREXTs OF THE cxamimng the physical featm'es of this sea (Plates 

 lndiax Ocean. YIII. and IX.), and stud}dng its conditions, we are 

 led to look for warm cmTents that have their genesis in this 

 ocean, and that carry from it volmnes of overheated water, pro- 

 bably exceeding in quantity many times that which is discharged 

 by the Gulf Stream fi^om its fountains (Plate YI.). The Atlantic 

 Ocean is open at the north, but tropical countries bomid the 

 Indian Ocean in that direction. The waters of this ocean are 

 hotter than those of the Carii)bean Sea, and the evaporating force 

 there (§ 300) is much greater. That it is greater we might, with- 

 out observation, infer from the fact of a higher temperatm^e and a 

 greater amount of precipitation on the neighboming shores (§298). 

 These two facts, taken together, tend, it would seem, to show that 

 large currents of warm water have their genesis in the Indian 

 Ocean. One of them is the well-known Mozambique current, 

 caUed at the Cape of Good Hope the Lagulhas cmTent. Another 

 of these warm cm-rents from the Indian Ocean makes its escape 

 through the Straits of Malacca, and, being joined by other warm 

 streams fi'om the Java and China Seas, flows out into the Pacific, 

 like another Gulf Stream, between the Philippines and the shores 

 of Asia. Thence it attempts the great circle route for the Aleutian 

 Islands, tempering climates, and losing itself in the sea as its 

 waters grow cool on its route towards the north-west coast of 

 America. 



391. Between the physical features of this, the " Black Stream" 



