380 



THE OCEAN. 



manage the " bell," and they lower it into the wa- 

 ter slowly until it reaches the bottom or until the 

 diver makes a signal to stop. The diving bell sinks 

 by its own weight. As it goes down, water cannot 

 get into it because it is full of air which cannot 

 escape. The air however becomes very dense and, at 

 great depths, very oppressive. 



When the bell touches the bottom, the diver gets 

 off the seat and works around inside the bell at 

 whatever is undertaken. He can have a light with 

 him, and various tools, and can labor for a short 

 time, as though not under water. The air however 

 soon becomes vitiated by his breathing and by the 

 burning of his light, so that he would suffocate after 

 a while, unless fresh air was supplied. Furnishing 

 fresh air by the means of a pump and tube connec- 

 ting with the bell was one of the first improvements. 



It has been found, in practice, however, that in 

 the very best form the diving-bell is a cumbersome, 

 clumsy affair. The latest and most approved model 

 is constructed in three compartments, one of which 

 is filled with compressed air, and one designed to 

 be filled with water, to assist in sinking the machine 

 while the whole apparatus is under the control of 

 the diver. But he is limited in his work to the 

 small space bounded by the sides of the bell. As this 

 heavy sub-marine house cannot be moved, in a later- 

 al direction, without great trouble and as the move- 

 ments of the diver is so closely circumscribed as 

 to render him useless in many kinds of submarine 

 work, a sort of w T ater-proof armor has been inven- 

 ted which seems to answer every purpose. 



