496 
selected to display the nonacoustical nature of the decay of the function 
with distance, The predictions of the similarity restraint theory for the 
case of Tetryl reflect the fact that the calculated initial value of the 
shock-wave energy is somewhat in excess of the mos probable value, determined 
from the maximum bubble radius. 
It may be concluded that the two different theories are in satis- 
factory agreement and that they give, on the whole, a good account of the 
experimental observations. The theoretical curves are very sensitive to 
the initial conditions, determined by the thermodynamic properties of the 
products of explosion. Although the calculation of the initial conditions 
is straightforward, it requires a knowledge of an applicable equation of 
state for the explosion products, These products exist at a high tempera- 
ture and very high pressure, a state that is inaccessible to direct experi- 
mental study, and the equation of state is mbject to considerable uncertainty. 
The calculations given in this section have been based upon thermodynamic 
properties of explosion products determined with the aid of anequation of 
state of a form proposed by Kistiakowsky and Wilson.4/ The parameters of 
this equation were determined from observed velocities of detonation for a 
series of explosives by methods which have been described Sieeunenee’/ 
Unfortunately, more recent experiment has resulted in a revision of the 
experimental detonation velocities which were employed for the evaluation of 
the equation of state parameters, and the equation of state is presently in 
need of revision. It appears probable that consistently satisfactory theo=- 
retical prediction of underwater shock-wave parameters could be achieved if 
an accurate equation of state for the explosion products were known. 
39/ S. R. Brinkley, Jr,, and E. B. Wilson, Jr. OSRD Report No. 905 (1942) 
102 
