4. When the enemy opens an artillery fire on a square, _preparatory to a cavalry charge_, his fire must cease when his cavalry approaches the square; say, on its arriving within one hundred and fifty yards. To avoid the artillery fire, the square may safely remain lying down until the hostile cavalry has reached this point. For, as they will require about half a minute to clear the intervening ground, the square will still have time enough left to rise, align its ranks, and deliver a volley before the cavalry reaches it. VII.--Defence against Cavalry. 1. The discipline of infantry is never put to a severer test than when it is required to resist a _charge of cavalry_, properly made. The moral effect of a charge of a body of horse at full speed, on the troops waiting to receive it, is like that caused by the swift approach of a locomotive under full steam, seeming quite as irresistible. It would be so in reality, but for the counter effect produced both on the horses and their riders by the sight of the infantry standing firm and reserving its fire. I have been told by an old cuirassier officer, who served through the campaigns of Napoleon with distinguished bravery, that there was no operation that his regiment so much dreaded as a charge upon well-disciplined infantry. 2. This counter moral effect on the charging cavalry is the greater, _the longer the infantry reserve their fire_; since, the less the distance at which it is delivered, the more fatal will be its effects. A volley at long range is not destructive enough to check the cavalry's advance; while this effect has often been produced by the infantry merely withholding its fire till the cavalry has approached very near; and a volley delivered at the very last moment has, in by far the greater number of instances, effectually repulsed the charge. Infantry should, therefore, let cavalry approach to within forty paces, or nearer still, and then give them a general volley. At the battle of Neerwinden, in 1793, the Austrian cavalry was repulsed by the French infantry under Dumouriez, by a volley poured in at the very muzzles of the pieces. At Austerlitz, a Russian cavalry charge on French infantry in line was repulsed by a volley delivered so near, that it stretched four hundred troopers on the ground. The rest dispersed in disorder to the right and left. 3. The armor of cuirassiers is bullet-proof. To repel a charge of these troops, therefore, it will be necessary to _aim at the horses_. Their armor is so heavy, that the mere fall of the riders on the ground is usually sufficient to disable them, as was the case with the French cuirassiers at Waterloo. 4. Infantry in line, in two ranks even, may withstand cavalry, if in compact order, and attacked _in front_. But the slightest cavalry charge on the flank of a line will rout it.