ur main body from any
especially dangerous sector such as ABC. Our cavalry is in front of our
first line and in touch with the enemy. The danger zone represents the
direction from which the enemy is expected.]

This plan must be modified according to the particular case. Let us
suppose that we are camping by a large body of water, or that we are
surrounded by mountains. We can easily imagine where we could change
the above general plan so as to give adequate protection and at the same
time lessen the number of men detailed for security. We must never
forget that men are generally tired when they arrive in camp, and that
we should make their work as light as circumstances permit. It requires
a nice judgment to choose the correct number for security.

We should know the names of these groups. Farthest away is the line that
sees, and reports what it sees, but can offer only a limited resistance.
This is called the "line of observation" or the "line of outguards." In
rear of the line of outguards we have larger groups placed at greater
distances. These are called "supports." This is the line that fights.
This is the line that makes extensive preparations for fighting (or
resisting). It is called the "line of supports" or the "line of
resistance."[2] We have one farther and last line of groups which is
still larger and occupies still greater distances than the two we have
just discussed. This is the safety valve and is called the "reserve," or
the "line of reserves." This is the line that gives a sound factor of
safety. It will only be called upon in cases of emergency and may
therefore generally enjoy a considerable degree of repose. But it and
the line of supports combined must have sufficient strength to delay the
enemy, in case of a general attack, long enough for our main body to
form for battle.

Let us look at the line of outguards for further important
considerations and distinctions. The enemy's movements and operations
should ordinarily be expected where there are for him least
difficulties. Large (dangerous) bodies of troops find trouble in
marshes, thick forests, steep mountainous country. They avoid these
obstacles as much as possible, selecting open country, solid soil,
strong bridges, and good roads. Here is where large and strong groups in
opposition are necessary. Small and unimportant groups (or no groups at
all) should be placed where the enemy's advance is exceptionally
difficult. Finally, there will b