WONDERS OF THE DEEP 81 



made in another rope to which a heavy stone 

 is attached, with which the diver sinks to the 

 bottom. 



The idea of supplying the diver with air while 

 he is under the water dates back to the sixteenth 

 century. In an old book written during that 

 period there is an engraving representing a diver 

 wearing a light-fitting helmet, to which is attached 

 a long leather pipe leading to the surface of the 

 water. By the use of a bladder the open end of 

 the tube was kept above the level of the water. 

 It is thought that this idea was suggested to the 

 inventor by the action of the elephant in keeping 

 its trunk above the water when it is crossing a 

 river. 



About a century later an apparatus was evolved 

 in which air was forced down to the diver by means 

 of a large pair of bellows. This possibly suggested 

 the air-pump, that was afterwards employed for 

 supplying the diver with air, and which is still the 

 method adopted in the majority of instances. 



Early in the nineteenth century, a Devonshire 

 man, John Lethbridge by name, invented a " water- 

 tight leather case for enclosing the person," and this 

 invention of a simple diving suit was the prototype of 

 the modern diver's dress. Made of leather, and con- 

 taining an ample supply of air, the diver could, by the 

 use of this suit, freely move his arms and legs, and 

 walk along the bottom of the sea. Lethbridge, it is 

 believed, made a considerable sum of money out of 

 his clever invention. 



