1248 
the acoustic approximation. For shocks of 1500 atmospheres 
in water, duration and impulse are respectively 1% and 8% 
less than the predictions of acoustic theory. In air for 
shocks of corresponding strength, namely 0.5 atmosphere 
overpressure, duration'‘and impulse are respectively 10% and 
4h greater than their acoustic approximations. Results of this 
report may be applied to current damage theories to estimate 
errors introduced by the use of the acoustic approximation . 
These errors may be very large if the target is close to the 
charge (e.g., contact mine, torpedo, depth charge, or a near= 
miss bomb), although they may be negligible if the target is 
attacked by a distant charse, such as one in an influence mine. 
