ILLUSTRATIONS 

 FIGURE Page 



1. Schematic diagram of apparatus used in experiments with aholehole. 3 



2. Pulse shapes. A. Nearly square wave used in experiments with aholehole. B. Wave of 



capacitor discharge used in experiments with tuna and other large pelagic fish; and 

 equivalent square wave. 4 



3. Relationship between total peak current (I) for satisfactory response and length of fish (L). 



Dashed line expresses the relationship I = 176/L 6 



4. The capacitor discharge circuit. A. Schematic diagram of complete system. B. Bank of 



fifty-five 1,000 mfd. capacitors 10 



5. The nnechanical interrupter. A. General view showing variable speed motor, contactor 



(one is removed), and drive cams. B. Close-up view of spring-loaded contactor. . . .11 



6. Power dissipation per unit volume of water vs. pulse frequency for satisfactory response 



in tuna 13 



