SEA WATER 225 



smashed inwards, so that eventually there would be no 

 air to buoy the ship up and it would be simply a mass of 

 solid iron and wood whose combined density would far 

 exceed that of the sea water surrounding, so that the 

 ship would be bound to sink to the bottom. Sir John 

 Murray said " During the Challenger expedition, after a 

 funeral at sea, the bluejackets sent a deputation aft to 

 ask if * Bill ' would go right to the bottom when committed 

 to the deep with a shot attached to his feet, or would he 

 ' find his level ' and there float about for evermore ? " 



It is said that a man at 2,000 fathoms would bear on his 

 body a weight equivalent to that of twenty locomotive 

 engines, each with a long goods train loaded with pig iron. 

 This was said however in 1873 when engines and trains 

 were considerably smaller than nowadays. One of the 

 effects of living at these great pressures is that when animals 

 are brought up quickly in the trawl they break to pieces 

 owing to the sudden reduction of pressure. 



Most sea animals must be able to stand a considerably 

 wide range of pressures as they are able to make large 

 journeys up and down. Whales when harpooned have 

 been known to " sound " as deep as four hundred fathoms. 

 Many small animals living in the drifting community 

 make upward journeys of fifty to a hundred metres or more 

 almost every night of their lives retiring to the deep levels 

 again in the daytime. In the laboratory small unicellular 

 animals have been subjected to pressures of as much as 

 600 atmospheres, without suffering any apparent harm. 



One of the most important conditions for life is light. 

 Without light there would be no plant life, for it is by the 

 help of the sun's rays that the plant can build up the 

 necessary starch and sugar from the carbon dioxide in the 

 air or in the water. Practically all animals are ultimately 

 dependent upon plant life for their food, and if in the sea 



