THE DEPTHS OF THE SEA 13 



As the weight or pressure of sea water is 

 well known we can readily compute the pres- 

 sures at the greatest depths and we know that 

 at a depth of one thousand fathoms the pres- 

 sure must amount to about one ton to the 

 square inch, while at three thousand fathoms 

 it is over three times as great. Such pressures 

 are almost beyond our imagination and are so 

 tremendous that thick, solid wood, when low- 

 ered to the depths of the sea is pressed full of 

 water and will not float, while thick glass or 

 metal globes with a small internal empty 

 space, after being lowered to these depths, are, 

 when again raised to the surface, found filled 

 with water, the liquid actually having been 

 forced through the surrounding material by 

 the pressure on every side. We can scarcely 

 conceive of animals existing under such con- 

 ditions, but in reality they are no more incon- 

 venienced by the pressure of the water than 

 are creatures on land troubled by the pressure 

 of the air. 



Moreover, here, far below the reach of day- 

 light, the temperature of the water never 

 changes and remains forever almost at the 



