§ 727. THE CLIMATES OF THE SEA. 359 



east, is pouring an immense volume of warm water into this part 

 of the ocean. As this water and the heat of the sun raise the 

 temperature of the ocean along the equatorial sea-front of this 

 coast, there is no escape for the liquid element, as it grows warm- 

 er and lighter, except to the north. The land on the south pre- 

 vents the tepid waters from spreading out in that direction as 

 they do to the east of S6° west, for here there is a space, about 

 18 degrees of longitude broad, in which the sea is clear both to 

 the north and south. They must consequently flow north. A 

 mere inspection of the plate is sufficient to make obvious the fact 

 that the warm waters which are found east of the usual limits as- 

 signed the Gulf Stream, and between the parallels of 30° and 40° 

 north, do not come from the Gulf Stream, but from this great 

 equatorial caldron, which Cape StRoque blocks up on the south, 

 and which dispenses its overheated waters up toward the fortieth 

 degree of north latitude, not through the Caribbean Sea and Gulf 

 Stream, but over the broad surface of the left bosom of the At- 

 lantic Ocean. 



727. Like the western half of the North Atlantic Ocean, the west- 

 The warmest sides of em half of cvcrv ouc of the thrcc great oceans is 



oceans and the cold- "^ n n • i 



est shores of conti- thc Warmer. The great now of warm water m the 

 tion. JSTorth Pacific is with the " Black Stream of Japan," 



on the Asiatic side ; in the South Pacific it is with the Polynesian 

 drift, on the Australian side : opposite to these, and on the eastern 

 side, are the Humboldt current in one hemisphere, and the Califor- 

 nia current in the other — cold currents both. In the South Indian 

 Ocean, the warm water is with the Mozambique current on the Af- 

 rrcan side, and the cold drift on the Australian ; and in the South 

 Atlantic, Plate IV. shows that, parallel for parallel, the littoral wa- 

 ters of Brazil are many degrees warmer than those on the Afri- 

 can side. Thus at sea the climatic conditions of the land are re- 

 versed, for the coldest side of the ocean is on the warmest side of 

 the continent, and vice versa. The winds from extra-tropical seas ' 

 temper the climates of the shores upon which they blow, not so 

 much by the sensible heat they convey as by the latent heat which 

 is liberated from the vapor they bring. This being condensed, as 

 upon the British Islands and Western Europe, sets free heat enough 

 not only to soften the climate, but to rarefy the air to such an ex- 

 tent as to be observed in the mean barometric pressure. 



