_The Director_: “We are now ready to proceed with the next step of the
problem, the posting of the first relief. Before we go into that I want
to make a few remarks about the location of sentinel posts.
“By day the sentinel must be able to see the whole of the ground
allotted to him for observation. He should be provided with sufficient
cover so that the enemy’s patrols will not be able to locate him. He
should have good communication with the outguard and the adjoining
sentinels. Excellent observation posts may sometimes be found in large
trees, one of the sentinels of the double post being located in a tree
and the other on the ground near the foot of the tree. It may be that
the best location for observation is also the best for resistance, in
which case the sentinels may be posted on or very near the actual
locality to be defended by the outguard. There is no objection to this,
provided the members of the outguard, as well as the sentinel, are well
concealed from the view of the enemy.
“The location of the sentinel post at night requires the most careful
consideration. It depends considerably upon the degree of darkness, and
consequently the value of eyesight as compared with hearing. On a very
dark night, when the sentinel can see only a few yards in front of him,
it is evident that his ears will be more useful than his eyes.
Furthermore, the difficulties of the enemy will be increased by the
darkness, and he is likely to make more noise by stumbling over unseen
obstructions. On a still night a sentinel posted on high ground can hear
better than when on low ground, because there is likely to be less
obstruction in the way of trees and other objects to interfere with the
sound waves passing through the atmosphere. It therefore appears that on
a very dark night, when the ears are more efficient than the eyes, the
sentinel should be posted on high ground, with low ground to his front.
“When the darkness is not so great and the powers of sight more nearly
approach in value the powers of hearing, it is better to place the
sentinel on low ground, with the sky line to his front. This is because
approaching persons will be silhouetted on the sky line and that it is
difficult to see when looking down from a height into a dark valley.
“The night post should always be provided with an obstacle placed from
10 to 30 yards to the front of the sentinel. It must be low, so that it
will not be seen by an approaching enemy. Its value is increased if a
wire or rope is attached to some object that will fall down with a loud
noise when anyone trips over the obstacle.”