ILLUSTRATIONS 



Pressure vessel, with fiber glass capsule and steel end 



cap assembled. Photograph. .. P^ge 6 

 End cap, with transducer bolted in place prior to assembly 



of pressure vessel. Photograph. . . ^ 

 Pressure vessel. Sectional. . . ^ 

 Pneumatic -hydraulic pump on calibration column in shed. 



Photograph. . . S 

 Attenuation as a function of frequency. . . 20 

 Directivity patterns of transducer inside and outside the 



capsule, 100 kc/s. . . 21 

 Directivity patterns of transducer inside and outside the 



capsule, 750 kc/s... IS 

 Directivity patterns of transducer at and 500 psig, 



24 kc/s. . . 14 

 Directivity patterns of transducer at and 500 psig, 



32 kc/s. . . 15 

 Complex impedance of B24FA transducer at and 500 



psig. . . 2^ 

 Transmitting response of B24FA transducer at and 500 



psig. . . 27 



REVERSE SIDE BLANK 



