34 



HAYES— DETECTION OF SUBMARINES. 



Sound from receivers i, 2, and 3 can be brought into phase at A 

 by rotating the groove to a proper position with respect to the fixed 

 openings i, 2, and 3. At the same time the three receivers of each of 

 the other three groups will be brought into phase at the points B, C, 

 and D respectively. 



/yf/ 



N<i.lPL£ 



■ifr y^ £ ^y/=£- H (? . 



o /^7=>£ /~/ s,/=! Tore 



Plate XIII. Principle of Type-H compensator. 



Sound from points A and B are conveyed through two fixed 

 grooves of equal length in the lower plate to another compensating 

 groove in the movable plate, the sound from B passing around the 

 end marked X and that from A passing the end marked Y. Both 

 sounds unite in a single path at E. The sounds from C and D are 

 similarly united in a single path at F. 



