570 



footnote on page 7 of this report, the corrections ar.ounting to as much 

 as 15^. The total water depth was 20 ft. The corrected period constants 

 are given in the last column of Tabl« XIV, 



Excluding the values at 1,75 ft (21 in.) for the reasons indicated 

 above, the average value of the period constant for pressed tetryl 

 is 4.iW-, and for loose tetryl is 4,57. These values show only a slight 

 scatter and are only about 1% higher than the corresponding ones in free 

 water* (s»e Tables III and VIIl), This higher result would indicate some 

 effect of the surface, not taken into account in the theory, which 

 becomes of importance when the bubble is within 2-3 radii of the surface. 

 However, considering that the total correction for the surface may be as 

 much as 15$, the aigreement is remarkably good. 



Note also that the difference between loose and pressed tetryl found 

 in the deeper shots is preserved here sQjiost quantitatively. 



TABLE nV 



FIRST PERIOD CONSTANTS FOR 25 GM TETRYL CHARGES 

 CLOSE TO THE SURFACE 



* Corrected for the effect of surface and bottom. 



** The values for l/2 lb charges. Those for 25 gm charges in free water 

 appear to be lower, but the evidence is not conclusive. 



■u- 



