In the passage of defiles in the face of an enemy, say, in the case of a river or swamp, the rule is for the column, as it emerges from the far end of the defile, to move in column of troops parallel to the river or swamp. It will thus (i.) be ready to wheel into line and attack quickly, (ii.) there is no fear of the column being pushed back on to succeeding troops coming through the defile, (iii.) the head of the defile is kept clear of troops, (iv.) there is one safe flank for your column, _i.e._ that on the side of the swamp or river, and (v.) there is not the same danger of the enemy pounding[32] an easy mark at the mouth of the defile with his artillery. If your own artillery can occupy any ground on this side of the defile, from which the exit can be seen, the accompanying diagram shows that a considerable force of your cavalry can make the passage with comparative safety under cover of its fire. It should always be remembered that the attack against troops, in course of the passage of a defile, will usually take place when only that proportion has crossed which the enemy thinks he can beat decisively. [Illustration: DIAGRAM VII.] A word of warning is necessary as regards a common and most enticing error, which is that of allowing squadron after squadron to be drawn into a fight. As regards the dissemination of squadrons, this would not be such a serious matter if every detachment would return immediately its rôle had been played; but unfortunately Providence does not appear to make commanders of detachments like that; if it did, automatically our force would become, say, one-quarter stronger.[33] CHAPTER VIII CAVALRY IN THE GENERAL ENGAGEMENT “It was thought that to engage the enemy to fight was our business.”--CROMWELL at Preston. “The part played varies according to the quality of the instrument and the capabilities of the operator.”--CHERFILS. In the last few years considerable prominence has been given to the action of independent cavalry, and there is reason to believe that this might lead to a large portion of the cavalry of an army being detached when a general engagement was imminent. This tendency may well arise where the general officer commanding has not a complete grasp[34] or perhaps belief in the possibility of a rôle for cavalry on the battlefield, nor entire reliance on them for that assistance, which, if properly trained and directed, they are well able to give.[35] The general officer commanding may, under the impression that the combat can be carried through by the artillery and infantry without much further assistance, order the cavalry commander to take the bulk of his squadrons and make a detour, involving half the night spent in the saddle, and thus place himself on the flank or rear of the enemy, and there to attack or wait his opportunity in the event of the enemy’s defeat.