The greater armies become, the more they are distributed over wide spaces and the more diversified the action and reaction of the different parts amongst themselves, the wider becomes the field of strategy, and, therefore, then the order of battle, in the sense of our definition, must also come into a kind of reciprocal action with strategy, which manifests itself chiefly at the extreme points where tactics and strategy meet, that is, at those moments when the general distribution of the combatant forces passes into the special dispositions for the combat. We now turn to those three points, the _division, combination of arms_, and _order of battle_ (_disposition_) in a strategic point of view. 1.—Division. In strategy we must never ask what is to be the strength of a division or a corps, but how many corps or division an army should have. There is nothing more unmanageable than an army divided into three parts, except it be one divided into only two, in which case the chief command must be almost neutralised. To fix the strength of great and small corps, either on the grounds of elementary tactics or on higher grounds, leaves an incredibly wide field for arbitrary judgment, and heaven knows what strange modes of reasoning have sported in this wide field. On the other hand, the necessity of forming an independent whole (army) into a certain number of parts is a thing as obvious as it is positive, and this idea furnishes real strategic motives for determining the number of the greater divisions of an army, consequently their strength, whilst the strength of the smaller divisions, such as companies, battalions, etc., is left to be determined by tactics. We can hardly imagine the smallest independent body in which there are not at least three parts to be distinguished, that one part may be thrown out in advance, and another part be left in rear: that four is still more convenient follows of itself, if we keep in view that the middle part, being the principal division, ought to be stronger than either of the others; in this way, we may proceed to make out eight, which appears to us to be the most suitable number for an army if we take one part for an advanced guard as a constant necessity, three for the main body, that is a right wing, centre and left wing, two divisions for reserve, and one to detach to the right, one to the left. Without pedantically ascribing a great importance to these numbers and figures, we certainly believe that they represent the most usual and frequently recurring strategic disposition, and on that account one that is convenient.