The best proportions for the quantity of artillery in an army is one gun for every 500 men (infantry), and one gun of the horse-artillery for every 250 men (cavalry); but this will vary much with the country in which it is to be used, hilly country requiring much less artillery than level country.
Armies, whether on the offensive or defensive, are generally kept in columns till the proper moment for deploying has arrived ; for by this disposition both parties are enabled to conceal their projects from each other till one of them has determined to commence the action, and each is in a condition to make such movements as may be necessary in order to give him an advantage over his opponent. The Spanish general, Cuesta, is blamed for having, at the battle of Medellin (1809), in which lie was defeated, advanced towards the French army in one weak line three miles long. when, by keeping the troops in columns, he might have moved them between the enemy's divisions, and thus, by separating them other, have destroyed them in detail. If a position is such that the army occupying it is exposed at several points to be attacked, those points should be occupied by small bodies of troops, the bulk of the army bCing kept behind in columns ready to march to any point where their services may be required. Thus the enemy will be embarrassed from the impossibility of determining the force of the army at any one point, and his only chance of success will lie in the quickness of his movements. The circumstances which may determine a general to attack a position at any particular point are, tho appearance of that point being weak on account of troops or artillery being withdrawn, from the ground being there more easy of access than elsewhere, or from its capabilities of affording cover to troops in their advance.
If an army, as A B, in position on level ground, is to be attacked on its left wing, n, the army acting against it is usually placed en Medan, as at at, N, r, Q, each division consisting of a battalion or a brigade ; and this formation may be accomplished by moving up the different columns, as at se, N', to the places which, when deployed, they are to occupy during the engagement. It would be advantageous, however, that the heads of the columns should remain till the moment of deployment in a line parallel to that of the enemy, in order to keep the latter as long as possible in suspense respecting the real point of attack. A favourable moment is then chosen for bringing the greatest
mass, as se, to the wing at B, which is supposed to be the weakest part of the line ; but it should be observed that this intention will succeed only when the different columns can be moved to their stations with great rapidity, for if the enemy has time to perceive the manoeuvre ho will not fail to take measures to counteract it. The Echelons must always be so near one another as to allow them to be mutually sup ported, yet not so near to the enemy as to be in danger of being forced into action. In order to explain the process of turning all enemy's position, let it be supposed that the left wing (a) of his line is in a plain, and not well protected by works, and, consequently, that it may be turned, while the right wing (A) is covered by woods. Strong columns are formed at it in order to perform the manoeuvre of turning the flank n. The divisions at x and P constitute the centre, and may be supposed to be on elevated ground, so as to be refused to the enemy ; while Q may consist of a small division extended along the skirts of the wood merely to keep the enemy in cheek.
Should the enemy reinforce his left, N, by drawing troops from his right, A, and should this circumstance become known after the troops m have set out on their march towards n, the infantry of the column if may then change their route and proceed towards x and r, conceal ing their strength as much as possible by passing through woods and hollow ways, if such there be, while the cavalry, supported by some infantry in a village, as at I, move towards at as before, in order to deceive the enemy. The central columns r and x then move towards their left. and unite with the tr000ps q to attack the wing A. Thus the disposition of the army is completely changed: and if the change is effected with rapidity, the enemy might not have time to reinforce the wing A before it would be turned. If the troops in the wing were to advance to attack the central column, at P and N, and these were to retire, those troops would be unable to produce any effect, as it would be necessary to recall them in a short time on account of the danger then threatening the right wing.