Every battle fought differs from all other battles, for no opposing forces ever meet under precisely identical conditions twice. Thus it is useless to speak of a typical battle except in the broadest general sense, and useless to attempt to describe a typical battle, or action of any kind. Usually, the artillery get into action after cavalry have reconnoitred the enemy’s position; the guns shell the enemy until he is considered sufficiently weakened to permit of infantry attack, and then the infantry go forward, even up to the rarely occurring bayonet charge. If their advance dislodges the enemy, the cavalry are set on to turn retreat into rout; if, on the other hand, the attacking force is compelled to retire, the cavalry cover the retreat, and, in order to make good in a retreat, a part of a force is taken back while the remainder hold the enemy in check. In modern actions, artillery fire their shells over the heads of their own infantry at the enemy, distance and trajectory permitting of this. By trajectory is meant the curve that a projectile describes in its flight; both rifles and big guns are so constructed and sighted that they throw their projectiles upward to counteract the pull of gravity, and the missile eventually drops down toward its object--it does not travel in a perfectly straight line. But it is bad for infantry to be in front of their own guns, with their own artillery shells passing over them, for too long--_morale_ suffers from this after a time, since a man cannot distinguish in such a case between his own artillery’s shells and those of the enemy. Whenever possible, the artillery in rear of an infantry force are posted slightly to either flank; circumstances, however, do not always admit of this.