278 THE ATLANTIC. [chap. v. 



l°-6 C. is maintained from a depth of 2000 fathoms to the 

 bottom. 



All the facts of temperature distribution in the Atlantic ap- 

 pear to favor the view that the entire mass of Atlantic water 

 is supplied by an indraught from the Southern Sea, moving 

 slowly northward, and interrupted at different heights by the 

 continuous barriers M'hich limit its different basins ; but this 

 involves the remarkable phenomenon of a vast body of water 

 constantly flowing into a cul-de-sac from which there is no exit. 

 When I suggested this view some years ago, I was asked, very 

 naturally, how it was possible that more water could flow into 

 the Atlantic than flowed out of it, and at that time I could see 

 no answer to the question, although I felt sure that a solution 

 must come some day. Now it seems simple enough ; but in 

 order to understand the conditions fully, I would ask my read- 

 ers to recall the appearance of the Atlantic — and of the Pacific 

 also, which is under exactly the same conditions — ^not on a map 

 on Mercator's projection, where the northern and southern por- 

 tions are necessarily greatly distorted, but on a terrestrial globe, 

 or on such a representation of part of a globe as we have in 

 the frontispiece to this volume. The earth may be divided 

 into two halves, aptly called by Sir Charles Lyell the land and 

 the water hemisphere, one of which contains the greater part 

 of the ocean, while the other includes almost all the land, with 

 the exception of Australia. On the globe one sees much more 

 clearly than on a map that the Atlantic is a mere tongue, as it 

 were, of the great ocean of the water hemisphere stretching up 

 into the land. The Arctic Ocean, with which it is in connec- 

 tion, is, again, a very limited sea, and nearly land-locked. The 

 North Pacific is another gulf from this water hemisphere, but 

 one vastly wider and of greater extent ; while the South Pa- 

 cific is included within the water hemisphere. 



Although from the meridional extension of the continents 

 to the southward, the water of the Atlantic is, as I have shown. 



