page 88 



THE WEB AND THE ROCK. This curious web- 

 shaped framework is the artificial electrical ground 

 of an ingenious instrument called a sonobuoy, used 

 to measure underwater sound waves produced by 

 the atomic bomb explosions. Each sonobuoy con- 

 sists of delicate listening apparatus beneath the 

 barrel-shaped float which houses an automatic 

 radio transmitter. Sound picked up by the buoy 



is transmitted to a distant listening post. The ver- 

 tical rod sprouting from the float is the antenna 

 for the transmitter. Use of such an artificial elec- 

 trical ground eliminated the effect of surface wave 

 motion on the instrument's operation. During the 

 war smaller types of sonobuoys were used to de- 

 tect submarines. Parachuted from a patrol plane, 

 they made accurate bombing possible. 



