TWO YOUNG NATURALISTS. 93 



two hundred, three hundred, and even five hundred 

 atmospheres. The result of the experiments proved 

 that fish that live near the surface can only descend 

 to a comparatively slight depth; under an increased 

 pressure they die ; and this is very remarkable the 

 water being forced into their tissues, their body 



SUBMARINE EXPLORATIONS OF THE " TALISMAN." SPONGE ( 



becomes rigid and brittle as glass. Naturally, the 

 simpler the organisation of the creatures, the greater 

 is their power of resistance, and a pressure that is 

 sufficiently great to kill a fish only stuns a crab, and 

 apparently does not produce much effect on a radiate 

 or a mollusc." 



