84 WONDERS OF THE DEEP 



waist-belt, in which he carries a strong knife in a 

 metal case for emergency purposes, and sometimes 

 any other small tools that may be essential for the 

 particular task he has in hand. 



The greatest depth to which any diver has 

 been known to descend is one hundred and eighty- 

 two feet. Those engaged in the Mediterranean 

 sponge fisheries frequently descend to a depth of 

 one hundred and fifty feet, while the pearl 

 divers of Australia go down a hundred and twenty 

 feet. 



For special kinds of work, such as laying the 

 foundations for bridges, breakwaters, etc., the diving 

 bell is employed. This consists of a cast-iron box 

 without a bottom, and weighs about five tons. 

 The top of the diving bell is supplied with stout 

 glass windows, so as to admit the light, and also 

 with a connection into which the air supply pipe, 

 which is connected to a force pump, is screwed. 

 Inside, the bell is fitted with two seats and a sus- 

 pending chain, to which immense stones or concrete 

 blocks can be attached. The bell is suspended from 

 a barge, or platform, by chains attached to the 

 top, and is used in from thirty to thirty-five feet 

 of water. 



In addition to its scientific and photographic 

 value, the Williamson deep-sea tube has many other 

 practical applications. One has only to read the 

 list of treasure ships which foundered in fairly 

 shallow water to realise what a fascinating field of 

 profit is here. Millions upon millions of pounds 



