LIQUIDS AND THEIR PROPERTIES 



87 



supply the diver with oxygen for his lungs; and second, to 

 overcome the pressure exerted by the water against his suit. 

 For example, if the diver is working at a depth of seventy 

 feet under water, the pressure upon his body is about three 



FIG. 37. A DIVER PREPARING TO GO INTO THE WATER 



On his shoulders the diver carries a cylinder of compressed air con- 

 nected by a tube with a machine for supplying the air. What pressure is 

 there upon every sq. dm. of his body at 100 dm. depth? 



times as much as at the surface. As long as he is provided 

 with air at a pressure sufficient to balance the pressure of 

 the water, his suit will fit loosely. A greater pressure of air 

 will tend to burst the suit; a smaller pressure will allow it 



