62 



DEPTHS OF THE OCEAN 



Trawling in 

 deep water. 



slightly warmed while sinking, just as happens with air that 

 suddenly sinks from a great height towards the earth. This 

 rise of temperature has also been attributed to decomposing 

 organic matter and to radio-active matter in the deposits at the 

 bottom. Whatever may have been the cause, we certainly 

 found a similar slight rise in the temperature of the deepest 

 layer on several subsequent occasions during our cruise. 



We next resolved to try the big trawl, and to reach the 

 bottom at 4700 metres we estimated that it would be necessary 

 to allow 8000 metres of wire, that is to say, 8 kilometres (Fig. 



Fig. 41.— The large Winch. 



41). We were engaged in paying out line from 5.30 p.m. to 

 7.15 P.M., and at midnight we commenced hauling in, which 

 lasted for about six hours. The trawl contained only two fishes 

 [Macrzcrus) and a number of lower forms of animals : holo- 

 thurians, a few worms, a gasteropod, a chalk-coloured crab, some 

 ascidians, and one or two other things (see Chapter VH.). 



This seemed to us such a poor catch that we came to the 

 conclusion that something had gone wrong. The trawl was 

 therefore dropped again, and could be seen sinking down in 

 perfect order. After being towed for three and a half hours, 

 it suddenly stuck fast and stopped the ship. Hauling in took 



