Cavalry increases the principle of mobility in an army. If too few in number the brisk flame of the elements of war is thereby weakened, because everything must be done slower (on foot), everything must be organised with more care; the rich harvest of victory, instead of being cut with a scythe, can only be reaped with a sickle.
An excess of cavalry can certainly never be looked upon as a direct diminution of the combatant force, as an organic disproportion, but it may certainly be so indirectly, on account of the difficulty of feeding that arm, and also if we reflect that instead of a surplus of 10,000 horsemen not required we might have 50,000 infantry.
These peculiarities arising from the preponderance of one arm are the more important to the art of war in its limited sense, as that art teaches the use of whatever forces are forthcoming; and when forces are placed under the command of a general, the proportion of the three arms is also commonly already settled without his having had much voice in the matter.
If we would form an idea of the character of warfare modified by the preponderance of one or other of the three arms it is to be done in the following manner:—
An excess of artillery leads to a more defensive and passive character in our measures; our interest will be to seek security in strong positions, great natural obstacles of ground, even in mountain positions, in order that the natural impediments we find in the ground may undertake the defence and protection of our numerous artillery, and that the enemy’s forces may come themselves and seek their own destruction. The whole war will be carried on in a serious formal minuet step.
On the other hand, a want of artillery will make us prefer the offensive, the active, the mobile principle; marching, fatigue, exertion, become our special weapons, thus the war will become more diversified, more lively, rougher; small change is substituted for great events.
With a very numerous cavalry we seek wide plains, and take to great movements. At a greater distance from the enemy we enjoy more rest and greater conveniences without conferring the same advantages on our adversary. We may venture on bolder measures to outflank him, and on more daring movements generally, as we have command over space. In as far as diversions and invasions are true auxiliary means of war we shall be able to make use of them with greater facility.
A decided want of cavalry diminishes the force of mobility in an army without increasing its destructive power as an excess of artillery does. Prudence and method become then the leading characteristics of the war. Always to remain near the enemy in order to keep him constantly in view—no rapid, still less hurried movements, everywhere a slow pushing on of well concentrated masses—a preference for the defensive and for broken country, and, when the offensive must be resorted to, the shortest road direct to the centre of force in the enemy’s army—these are the natural tendencies or principles in such cases.
These different forms which warfare takes according as one or other of the three arms preponderates, seldom have an influence so complete and decided as alone, or chiefly to determine the direction of a whole undertaking. Whether we shall act strategically on the offensive or defensive, the choice of a theatre of war, the determination to fight a great battle, or adopt some other means of destruction, are points which must be determined by other and more essential considerations, at least, if this is not the case, it is much to be feared that we have mistaken minor details for the chief consideration. But although this is so, although the great questions must be decided before on other grounds, there still always remains a certain margin for the influence of the preponderating arm, for in the offensive we can always be prudent and methodical, in the defensive bold and enterprising, etc., etc., through all the different stages and gradations of the military life.
On the other hand, the nature of a war may have a notable influence on the proportions of the three arms.