HYDROPHONE 



NEL AMPLIFIER 

 EARPHONES 

 BATTERY BOX 



TRANSDUCER 

 AUDIO OSCILLATOR 

 AUDIO AMPLIFIER 



B 



INNER GATE PORTS 



/ 



^q <!>, 



Q 



DEEP 

 SHALLOW 



>r 



TRANSDUCER ^ HYDROPHONE 



.. ^ L 



FILL 



-T-T 



FILL 



^f: 



TV^ 



FIG. 17 DIAGRAM OF THE TANK (A) AND POND(B) SHOWING THE POSITION 

 OF THE TRANSMITTER AND RECEIVER USED IN EXPERIMENTS WITH 

 SOUND. 



61 



