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.

[12] Mahan, _War of 1812_, i, 316.

If, then, we exclude the meaning of mere assembling and the meaning of the
mass, we have left a signification which expresses coherent disposal about
a strategical centre, and this it will be seen gives for naval warfare just
the working definition that we want as the counterpart of strategic
deployment on land. The object of a naval concentration like that of
strategic deployment will be to cover the widest possible area, and to
preserve at the same time elastic cohesion, so as to secure rapid
condensations of any two or more of the parts of the organism, and in any
part of the area to be covered, at the will of the controlling mind; and
above all, a sure and rapid condensation of the whole at the strategical
centre.

Concentration of this nature, moreover, will be the expression of a war
plan which, while solidly based on an ultimate central mass, still
preserves the faculty of delivering or meeting minor attacks in any
direction. It will permit us to exercise control of the sea while we await
and work for the opportunity of a decision which shall permanently secure
control, and it will permit this without prejudicing our ability of
bringing the utmost force to bear when the moment for the decision arrives.