1455 
the boundary between disturbance and undistorted propagation. 
It should be noted that a more complete determination of that 
boundary over the curves of equal pressure was not possible for 
this test because a time scale had not been recorded. 
The theoretical curve is drawn also in Fig. 10. It was 
derived from the known charge weight and the distances assuming 
a spherical charge (instead of the cylindrical charge which was 
used) and neglecting the difference between Pentolite and the 
used Tetryl. The agreement is good. 
It is interesting that the consideration concerning the 
range of disturbance can be applied to another problem. In Ref. ll 
the pressure distribution around a cylindrical charge in water has 
been determined. It could be shown that the curves of equal pres- 
sure initially are parallel to the charge surface and that this 
parallel part gradually becomes smaller for smaller pressures due 
to the propagation of disturbances produced at both ends of the 
charges and propagating along the wavefront. A theoretical boundary 
for the propagation of the disturbance could not be derived because 
the critical angle has only been calculated for pressures up to 
10000 at. (pressured up to 50000 at. occur here), but mainly because 
of the fact that the detonation wave has to propagate over a certain 
length of the cylindrical charge before the detonation becomes 
steady. 
27 
