THE DEEP SEA 



with water through and through their bodies. A 

 delicate structure like Venus 's flower- basket 

 (Euplectella), which is shivered in a child's fingers, 

 lives in depths where there are tons of pressure on 

 the square inch. The whole body is open to the 

 water and the pressure is not felt. For while a 

 hermetically sealed glass vessel is crushed in when 

 it is lowered into deep water, an open glass vessel, 

 no matter how delicate, is not affected. On the 

 Challenger expedition, Mr. J. Y. Buchanan made an 

 instructive experiment which has been often cited, 

 He took a hermetically, sealed empty glass cylinder, 

 wrapped it up in flannel, enclosed it in a copper 

 cylinder with perforated ends, and lowered it to 

 2,000 fathoms. At a certain depth the glass cylinder 

 was shivered into snowy powder, for its walls could 

 not withstand the increasing outside pressure of the 

 water. The shivering took place so suddenly that 

 before water could rush in to fill the vacant space, 

 one side of the copper cylinder caved in. As Prof. 

 Wyville Thomson said, an "implosion," not an 

 explosion, occurred. 



When a Deep-Sea fish rising suddenly gets into a 

 zone of much reduced pressure, the gas in its swim- 

 bladder, which had its pressure adjusted to the 

 greater depth, expands, and the fish, in spite of 

 itself, is hurried to the surface, " tumbling upwards," 

 as Professor Hickson puts it. The transition is too 

 rapid for a readjustment to be made. 



Another fitness at once intelligible is the fine 

 display of touch organs, as is natural enough in a 

 world of darkness. There may be feelers longer 



215 



