corps--240,000 men--it is quite another matter. The turning of any one
of these great bodies through a whole right angle is a lengthy
business. You cannot put a quarter of a million men into one
column--they would take ages to deploy--so you must, as we have seen,
make each unit of them overlap the next before the turn can begin.

[Illustration: Sketch 29.]

[Illustration: Sketch 30.]

Nor is that all the delay involved. It would never do for these six
separate corps to come up in driblets and get defeated in detail; 10,
11, and 12 will have to wait until 13, 14, 15, and even 16, have got
up abreast of them--and that is the third cause of delay.

Here are three causes of delay which, between them and accumulated,
have disastrous effect; and in general we may be certain that where
very large bodies and very extensive stretches of territory are
concerned, that wing of Black which has been left out in the cold can
never come up in time to retrieve the situation created by White's
twelve pinning Black's engaged wing of only nine.

If the square has worked, and if the twelve White have pinned the
right-hand wing of Black, 1 to 9 inclusive, there is nothing for Black
to do but to order his right wing, 1 to 9, to retreat as fast as
possible before superior numbers, and to order his left wing, 10 to
16, to fall back at the same time and keep in line; and you then have
the singular spectacle of twelve men compelling the retreat of and
pursuing sixteen.