For instance, in the above diagram, he may not know whether the blow
is coming from the precise direction 1, or 2, or 3, but he knows that
it is coming somewhere within the sector XY.

Then he will draw up his square so that its various bodies all face
towards the average direction from which the blow may come.

The SIZE of his square--which is of great importance to the
result--he makes as restricted as possible, _subject to two prime
conditions_. These conditions are:--

First, that there shall be room for the troops composing each corner
to be deployed--that is, spread out for fighting. Secondly, that there
shall be room between any two corners (A and C, for instance) for a
third corner (D, for instance) to move in between them and spread out
for fighting in support of them. He makes his square as close and
restricted as possible, because his success depends--as will be seen
in a moment--upon the rapidity with which any one corner can come up
in support of the others. But he leaves enough room for the full
numbers to spread out for fighting, because otherwise he loses in
efficiency; and he leaves room enough between any two squares for a
third one to come in, because the whole point of the formation is the
aid each corner can bring to the others.

In this posture he awaits the enemy.

That enemy will necessarily come on in a lengthy line, lengthy in
proportion to the number of his units. For it is essential to the
general commanding _superior_ numbers to make the _whole_ of the