1448 
are applied, it will be seen: 
Ff VGR emp - mp 
and if y<«<d =, it is possible to simplify 
WA, 
ay = Ves ae = d 
Ee eae F (18) 
This can be integrated and gives 
yz ee 7 = / 
’ y 724% 4% Fae ~_d bre +€ 
Considering the condition y(r..;4) = 0, it will be derived 
g -2d{in -/- Gtr $ (19) 
with ns Te orst (19a) 
It should be remembered that this formula holds only for pres- 
sures 7 £500 at at the critical distance and for depths of 
that boundary of surface disturbance which are small compared 
with the charge depth (7 << d). 
For smaller charge depths, that is, for the range of small 
depths where the pressures are too high and the approximations 
therefore are no more correct, the boundary of the range of dis- 
turbance can be derived directly. This is not difficult if the 
20 
