Upon the distance of the object from the battery; upon the difference of level between these points; the distance of the desired point of fall from the parapet; the height of the parapet, &c.
9. If the embrasure be such that the object is masked, how is the piece pointed?
The direction must be given, as with the mortar, by the plummet; this is held by the person who points, in such a manner as to cover both the line of metal and the object. The elevation is then given by the quadrant.
10. What is the maximum angle of elevation in ricochet firing?
Against troops it should seldom exceed 3° above the surface of the ground occupied by them. Against fortresses, forts, and fortified lines, it varies from 3° to 9° above the horizontal.
11. At what distance from the object should the ricochet battery be placed?
Never at a greater distance than 600 yards.
75]
12. In enfilading a work, how should the ricochet firing be conducted?
The projectile should be made to graze the parapet while in the descending branch of the trajectory; and this must be effected by regulating the charges and elevating or depressing the piece until the shot is seen to fall just over the interior crest of the parapet. Light charges are generally used, varying from two-thirds to one-eighth of the ordinary charge.