728 



02*, bi', b2'. It is to be noted from Graph k that the maxlraim of the first positive phase 

 occurs approximately at a time when a so-called shallow wave will arrive, i.e., "t = /^ 

 It is also noteworthy that the maxima, minima, and zeros of corresponding phases of 

 G ( h! , ti' ), Gi, k hJ , , t'), and G {/!.', fT^ ) all have about the same values 



of t , wherever computed. (This fact seems to hold also for (£ . ^' (/I'^O ,t' ) ^where 



In order to evaluate G > y' , it is necessary to know the period of the gas globe. 

 The first period T can be obtained approximately from the folloviing expression ^' for a 

 spherical globe in an incompressible, inviscid liquid bounded by a rigid sea bed parallel 

 to the free surface, and subject to atmospheric pressure ( rl. , in units of length); 



where r ( -^^ ) is a knovm function of X 

 and ^ s / - ^ Z^ 



3, 



where ^ is the amount of residual energy in the gas and the liquid after the shock wave 



has passed. If E is assumed to be 50^6 of the adiabatic, constant-volune heat of explosion, 



which has been computed -i) to be 1060 cal/g for TNT, then Li can be expressed as follows 



in terms of the charge weight IV , where W is given in pounds and TX in feet. 



3/ 



^-^^■'\f^: 



■33 



Some values of L of practical interest are given in Table 2. 



. Table 2 



\v(lb) 

 n(ft)\ 222 1200 2100 6600 



U »- U L. 



25 2^.21 



30 23.55 



35 22.96 36.45 



40 22.43 35.60 



45 21.94 34.82 



50 21.49 34.11 



55 21.07 33.45 



60 20.68 32.84 



70 19.99 31.74 



80 19.39 30.77 



90 18.84 29.92 



100 18.36 29.15 



110 17.92 28.45 



120 17.52 27.82 



22 



