THE liOYAL ARTILLERY INSTITUTION, 
399 
glance off point first, .when there is not enough plastic distortion to hold 
the point, 
and base first when the point is caught but not held. 
Lastly, Mr. Mallet notices the conditions which cause a shot to 
ricochet on water (in spite of the slight tendency there is to turn down¬ 
wards before the head becomes immersed, owing to the inequality of 
the resistances on the front of it), the coefficient of resistance being much 
less on the upper side. 
Comparing the wave AA to that caused by an earthquake (vide the 
53 
