THE GREAT DEEPS III 



The fish is therefore unable to go down to 

 the bottom again, but rises helplessly, and 

 more and more rapidly, until it reaches the' 

 surface, usually dead, with its body greatly 

 distended, and sometimes even split open. 



VERY COLD 



The deep sea is a very cold haunt, for the 

 sun's heat is practically lost at about 150 

 fathoms; and there is a continual sinking 

 down of cold water, rich in oxygen, from the 

 Poles, especially from the South. Throughout 

 the year there is little variation in the abyssal 

 temperature, which remains at about 28-34 

 Fahrenheit, a little on each side of the freez- 

 ing-point of fresh water. Eternal winter 

 reigns. There are cleverly made thermome- 

 ters for taking the temperature of the abysses ; 

 thus, after the well-protected thermometer 

 has been down for a while, a metal " mes- 

 senger" is sent spinning down the wire, which 

 hits a spring and turns the thermometer up- 

 side down, so that it cannot change on the way 

 up. In a similar way water-bottles that collect 

 samples of the water at various depths can 

 be automatically closed at any point. 



