2. In the Austrian service, squares formed by a _column in mass_ are considered preferable to hollow ones, on the supposition that though horses will recoil from a dense mass, they may be easily brought to break through a shallow formation, over which they can see the open ground. But this theory seems to be refuted by numerous facts. A large proportion of the formations that have successfully repulsed cavalry, since the beginning of this century, have been hollow squares. 3. The rule laid down in the Tactics (Par. 143, Skirmishers), directing the skirmishers, in rallying on the square, to "come to a ready without command, and fire upon the enemy; which will also be done by the reserve, as soon as it is unmasked by the skirmishers," is an unsound one, for a compliance with it would be dangerous. A square cannot expect to repulse cavalry by an irregular fire at will, but only by well-directed _volleys_. If cavalry charge a square firing irregularly, it will probably rout it. On the other hand, if a square wait coolly till the cavalry is at twenty paces, its volley will be murderous. At Waterloo, the Allied squares that reserved their fire till the French cavalry had arrived at from twenty to forty paces, invariably repulsed it. At that battle, Ney led eleven cavalry charges against the British squares, every one of which failed. At the opening of the campaign of 1813, Napoleon had, comparatively, but a handful of cavalry; so few, that they had to keep close to their infantry for protection. In crossing the plains of Lutzen, a large and splendid cavalry force of the Allies, supported by infantry and by horse-artillery, made an attack on Ney's corps, which consisted chiefly of young and raw recruits, who saw an enemy for the first time. The situation was extremely dangerous, and Ney and his principal generals threw themselves into the squares to encourage them. By volleys delivered at a signal, the enemy's charges were all repulsed, and the conscripts acquired great confidence from the ease with which this was done. Ney then broke up his squares, and, pursuing the enemy in columns, completed their repulse. At Auerstadt, in 1806, Davoust's French squares had to sustain a long succession of charges from ten thousand Prussian horse. By reserving their fire, each time, to within thirty or forty paces, its effect was so deadly, that a rampart of dead and disabled men and horses was soon formed around the squares, and the charges were all repulsed. So, at Jena, on the same day, Ney, posted in a square, allowed the Prussian cuirassiers to charge up to within fifteen or twenty paces, when the front attacked, at his word of command, poured in a fire which completely repulsed the charge, strewing the whole ground with dead and wounded. The Prussian cavalry, in that battle, are said to have been "terrified at the sight of a motionless infantry reserving its fire."