26 THE DEPTHS OF THE SEA 



such numbers do they fall, that large areas of the 

 ocean bed are covered with a thick deposit of their 

 shells. In the shallower waters the foraminifera, with 

 their calcareous shells, prevail, but over the deeper 

 abysses of the ocean they take so long in falling that 

 the calcareous shells are dissolved in the water, which 

 contains a considerable proportion of carbonic acid 

 gas, and their place is taken by the siliceous skeletons 

 of the radiolarians and diatoms. Thus there is a 

 ceaseless falling of organisms from above, and it must 

 be from these that the dwellers of the deep ultimately 

 obtain their food. As Mr. Kipling in his ' Seven Seas,' 

 says of the deep-sea cables : 



' The wrecks dissolve above us ; their dust drops down 

 from afar — 

 Down to the dark, to the utter dark, where the blind 

 white sea-snakes are.' 



In trying to realize the state of things at the bottom 

 of the deep sea, it is of importance to recognize that 

 there is a wonderful uniformity of physical conditions 

 la-has. Climate plays no part in the life of the depths ; 

 storms do not ruffle their inhabitants ; these recognize 

 no alternation of day or night ; seasons are unknown 

 to them ; they experience no change of temperature. 

 Although the abysmal depths of the polar regions 

 might be expected to be far colder than those of the 

 tropics, the difference only amounts to a degree or so 

 — a difference which would not be perceptible to us 

 without instruments of precision. The following data 

 show how uniform temperature is at the bottom of 

 the sea. 



In June, 1883, Nordenskiold found on the eastern 

 side of Greenland the following temperatures : at the 

 surface 2*2° C. ; at 100 metres 57" C. ; at 450 m. S'l ° C. 

 In the middle of December, 1898, the German deep- 

 sea expedition, while in the pack-ice of the Antarctic, 



