In the Russian service each, battalion has four divisions of three ranks each.  But the third rank is employed as tirailleurs, which gives a depth of column of eight files.  The employment of the third rank for tirailleurs is deemed objectionable on account of the difficulty of rallying them on the column.  For this reason, the best authorities prefer detaching an entire division of two companies.

The formation of squares is exceedingly effective in an open country, and against an enemy who is superior in cavalry.  Formerly very large squares were employed, but they are now formed either by regiment or by battalion.  The former are deemed best for the defensive, and the latter for offensive movements.  The manner of arranging these is shown in Figure 29.

3d.  The mixed system, or the combination of the two preceding, has sometimes been employed with success.  Napoleon used this formation at Tagliamento, and the Russians at Eylau.  Each regiment was composed of three battalions, the first being deployed in line, and the other two formed in columns of attack by division in rear of the two extremities, as shown in Fig. 30.  It may in some cases be better to place the second and third battalions in line with the first, and on the two extremities of this battalion, in order to prolong the line of fire.  The centre of the line of each regiment would be less strong, however, than when the two battalions by column are placed in rear of the other which is deployed.  This mixed system of formation has many advocates, and in certain situations may be employed with great advantage.

4th.  The deep order of heavy columns of several battalions is objectionable as an habitual formation for battle, inasmuch as it exposes large masses of men to the ravages of artillery, and diminishes the mobility and impulsion of an attack without adding greatly to its force.  Macdonald led a column of this kind at the battle of Wagram with complete success, although he experienced enormous losses.  But Ney’s heavy columns of attack at Waterloo failed of success, and suffered terribly from the concentric fire of the enemy’s batteries.

Whenever deep columns are employed, Jomini recommends that the grand-division of twelve battalions should have one battalion on each flank, (Fig. 31,) marching by files, in order to protect its flanks from the enemy’s attacks.  Without this defence a column of twelve battalions deep becomes an inert mass, greatly exposed to be thrown into disorder or broken, as was the column of Fontenoy, and the Macedonian phalanx by Paulus Emillus.  A grand-division is sometimes arranged in two columns by brigade, as is represented in Figure 32.  These are less heavy than a single column of grand-division by battalion, but are subject to nearly the same objections.

All offensive operations on the field of battle require mobility, solidity, and impulsion; while, on the other hand, all defensive operations should combine solidity with the greatest possible amount of fire.