730 



Small-scale experiments ^' Indicate that Its size is slightly less than that of the complete 

 gas globe at a distance of 1.2 Li from the wedl. In view of the lack of sufficient quanti- 

 tative information, however, the actual volvnne V^ on the bottom will be assumed here to 

 be half of V • (In case of venting at the surface a better approximation is the volume 

 of a cylinder of a height equal to the depth of the water and of a radius slightly less 

 than the maximum spherical globe in an unbounded liquid.) 



Thus we obtain finally for the pressing -p { /v', ,'t ) on the bottom due to the 

 first pulsation from an explosion originating also on the bottom (cf. expression (5'^ 



Expressing the pressure as "t) ( /t. , 5 , t ) in feet we have for TOT 



The minimum pressure ^ (A-j ^ t^ ) f°r 'the first negative phase is represented as a 

 function of the depth ft for various values of the charge freight W in Graphs 5a» b, c, d 

 e, f, corresponding to values of A- equal to 5, 10, 15, 25, 50, 500, respectively. 



A comparison of these calculated values with available experimental ones shows 

 satisfactory agreement in consideration of the various approximations that have been made. 

 It will be reported in detail elsewhere. 



24 



