Cavalry may also be very efficacious against infantry in wet weather, when the rain or snow renders it impossible for the foot soldiers to use their fire-arms to advantage, as was the case with the corps of Augereau, at Eylau, and with the Austrian left, at the battle of Dresden. Again, if the infantry be previously weakened, or thrown into disorder by the fire of batteries. The charge of the Russian cavalry at Hohenfriedberg, in 1745, is a remarkable example of this kind.
Cavalry should always be immediately sustained in its efforts either by infantry or other bodies of horse; for as soon as the charge is made, the strength of this arm is for a time exhausted, and, if immediately attacked, defeat becomes inevitable. The charge of the cavalry of Ney on Prince Hohenlohe at the battle of Jena, and of the French horse on Gossa at Leipsic, are fine examples of the successful charges of cavalry when properly sustained. Kunnersdorf and Waterloo are examples of the disastrous consequences of leaving such charges without support.
The choice of the field of battle is sometimes such as to render cavalry almost useless. Such was the case at the battle of Cassano, between the Duke of Vendome and the Prince Eugene. The field was so cut up by the Adda and the canals of Rittorto and Pendina, that Prince Eugene could make no use of his horse. If, when master of the bridge of Rittorto, he had been able to charge the French with a body of cavalry, there had been no doubt of his complete success.
After a battle, and in the pursuit of a flying enemy, cavalry is invaluable. If Napoleon had possessed a suitable number of mounted troops, with an able commander, at the battles of Lutzen and Ligny, the results of these victories had been decisive; whereas they were really without consequence. On the other hand, the Prussian army in 1806, after the battle of Jena, and Napoleon's army in 1815 at Waterloo, were completely cut to pieces by the skilful use of cavalry in the pursuit of a defeated and dispirited foe.
The want of good cavalry was severely felt in the war of the American Revolution. Had Washington possessed a few good squadrons of horse, his surprise and defeat in the lines of Brooklyn, and the consequent loss of New York, had never taken place. The efficient employment of a few good squadrons of cavalry might readily have prevented the defeat at Bladensburg, and the loss of the capitol, in 1814.
In a well-organized army, the cavalry should be from one-fourth to one-sixth of the infantry, according to the nature of the war.[[32]]
To gain a competent knowledge of the duties connected with the two arms of service mentioned in this chapter, the officer should make himself thoroughly acquainted with Scott's System of Infantry Tactics, for the United States' Infantry, or at least with Major Cooper's abridged edition of Infantry Tactics, and with the system of Cavalry Tactics, adopted in our army; also with the directions for the use of these two arms in a campaign, and their employment on the battle-field, given in the writings of Jomini, Decker, Okouneff, Rocquancourt, and Jacquinot de Presle.
The following books may be referred to for further information respecting the history, organization, use, and instruction of infantry and cavalry:—