Which meaning, then, is most closely connected with the ordinary use of the word?  The dictionaries define concentration as “the state of being brought to a common point or centre,” and this coincides very exactly with the stage of a war plan which intervenes between the completion of mobilisation and the final massing or deployment for battle.  It is an incomplete and continuing act.  Its ultimate consequence is the mass.  It is a method of securing mass at the right time and place.  As we have seen, the essence of the state of strategic deployment to which it leads is flexibility.  In war the choice of time and place will always be influenced by the enemy’s dispositions and movements, or by our desire to deal him an unexpected blow.  The merit of concentration, then, in this sense, is its power of permitting us to form our mass in time at one of the greatest number of different points where mass may be required.

It is for this stage that the more recent text-books incline to specialise concentration—­qualifying it as “strategic concentration.”  But even that term scarcely meets the case, for the succeeding process of gathering up the army into a position for tactical deployment is also a strategical concentration.  Some further specialisation is required.  The analytical difference between the two processes is that the first is an operation of major strategy and the other of minor, and if they are to be fully expressed, we have to weight ourselves with the terms “major and minor strategic concentration.”

Such cumbrous terminology is too forbidding to use.  It serves only to mark that the middle stage differs logically from the third as much as it does from the first.  In practice it comes to this.  If we are going to use concentration in its natural sense, we must regard it as something that comes after complete mobilisation and stops short of the formation of mass.

In naval warfare at least this distinction between concentration and mass is essential to clear appreciation.  It leads us to conclusions that are of the first importance.  For instance, when once the mass is formed, concealment and flexibility are at an end.  The further, therefore, from the formation of the ultimate mass we can stop the process of concentration the better designed it will be.  The less we are committed to any particular mass, and the less we indicate what and where our mass is to be, the more formidable our concentration.  To concentration, therefore, the idea of division is as essential as the idea of connection.  It is this view of the process which, at least for naval warfare, a weighty critical authority has most strongly emphasised.  “Such,” he says, “is concentration reasonably understood—­not huddled together like a drove of sheep, but distributed with a regard to a common purpose, and linked together by the effectual energy of a single will."[12] Vessels in a state of concentration he compares to a fan that opens and shuts.  In this view concentration connotes not a homogeneous body, but a compound organism controlled from a common centre, and elastic enough to permit it to cover a wide field without sacrificing the mutual support of its parts.