295 
= Jia 
Correcting this last formula to make P depend on wild the best Interpretation of the 
experimental results is obtained with the formula 
pP = 1600 w/3/p 1b. Asquare Inch. 
Since the theory cannot be relied on to within 10 of 20%, the agreement with experiment 
is quite satisfactory. 
An approximate calculation of the pressure-time curve for a 300 1b. charge at 50 feet, 
based on Figure 5, gives results agreeing very closely with the experimental data, as shown in 
Figure 6, Figure 7 shows some of the pressure ana velocity distribution curves at various steps. 
Energy distribution throughout the system. 
Although the close agreement between the theoretical and experimental pressure-time curves 
ts extremely satisfactory, the accuracy of the experimental curves was never in question. 
The theory, however, does provide valuable new information about the enerjy distribution 
throughout the system. 11 that is known experimentally Is that roughly one-quarter of the 
chemical energy of the charye resides in the pressure pulse at the stage where the peak pressure 
is down to 1 ton/square inch. (See, for example, Wood, Report "8"), 
At any stage In the motion, tne energy may be sud=divideo as followsi— 
(1) Kinetic energy of water (T)) 
(2) Potential energy of water (V4) 
(3) Irreversible heating of water, or wastage (w) 
(4) Kinetic energy of gas (T,) 
(5) Potential energy of gas {v,) 
Of these, (1) and (4) call for no comments; (2) merety represents the eneryy stored as 
compression In tne water; (4) also may be regarded as energy stored by comoression, but the 
ultimate seat of energy here Includes chemical as well as pressure energy because the chemical 
composition of the gas varles along the adlabatic; (3) is the ordinary wastage associated with 
shock waves (an account of the wastage assoclated with shock waves In water is given earlier In 
this paper). 
The following table has been constructed to show the energies of the five categories when 
the shock wave front Is at x-charge radi} (initial density of charge 1.5), the units being calories 
per gramme of T.N.T. 
Tne sum of the energies along any row should, of course, equal the total energy of the 
explosive (here taken to be 800 cal./gm,), but because of the difficulty of maintaining accufacy 
in the inner regions of the bubble, the values of T, and Y, in the latter stages are only rough, 
The first three columns, however, are reasonably accurate, 
Figure 8 shows how the wate~ acquires useful eneryy (i.e. T¢ v) as a function of x, 
The remarkable feature of the cutve Is the extremely rapid rise near the beginning (x= 1). One 
might oes 
