32 



HAYES— DETECTION OF SUBMARINES. 



in phase for sound coming from any particular direction by properly 

 adjusting the compensator. Also a similar adjustment of each 

 compensator in the other three groups will bring the response from 

 the three receivers of each group in phase at their respective junc- 

 tions B, C, and D. 



For convenience the four junctions A, B, C, and D may be re- 

 garded as four separate receivers located at points 2, 5, 8, and 11 

 respectively. The responses from A and B can be brought together 



~3^ -(^ 



Plate XII. Principle of M-V tube. 



in phase at E by means of another "■2-Spot" compensator and sim- 

 ilarly the responses from C, and D can be brought in phase at F. 



Points E and F may, for convenience, be regarded as two sepa- 

 rate receivers located at a point midway between 3 and 4 and be- 

 tween 9 and 10 respectively. These two receivers connect with the 

 ears through another compensator and the stethoscope leads L and 

 R, and by properly adjusting the compensator the sound can be bi- 

 naurally centered and the direction of the sound source determined 

 with an ambiguity as to port or starboard. This ambiguity is readily 



