traverse system as employed in Section I to be continued, the narrow
single-traffic C. T.’s, from wear and tear and shell fire, soon become
wider, and as the width would allow rapid transit to friend and foe
alike, it is of the utmost importance that some means be adopted to
deprive the enemy of this advantage. Moreover, the enemy may have
successfully advanced down on traversed C. T., say, at “C,” and our
own bombers might still be fighting in another traversed C. T., say,
at “D,” and their needs demand protection. This may be obtained if,
before the single C. T.’s merge into the double, each of them be quite
straight for approximately 15 yards, and island-traverse, “E,” be
placed at the junction. In the rear of this island, “E,” is a large
and substantial recess, into which one or two Lewis guns or automatic
rifles can be placed, firing through loopholes and rendering hostile
advance down both “C” and “D” communication trenches almost impossible.
The recess in “E” must allow ample room in which to operate. Overhead
cover is provided, and one rifle would require one long loophole, so
that it could fire along either C. T. without more than a moment’s
interruption. In the case of two rifles being available, there could be
two such long loopholes, each covering both C. T.’s, one for kneeling
and one for standing. The lower loophole gives the advantage of it
being impossible for any of the enemy to get out of danger beneath it.
The fact that the traverse is an island one, with passageway either
side, would allow friends to advance round the traverse and up “D” to
the support of friends still fighting there, and without obstructing
the fire directed from the traverse at enemy advancing down “C.”
[Illustration: _ISLAND TRAVERSE_
A type used to control long, straight stretches of trench.]
An island-traverse so constructed and manned should be unapproachable
along either trench “C” or “D,” but precautions must be taken to
prevent the enemy avoiding it by coming out into the open, as in active
moments C. T.’s become as mutilated as fire trenches and the enemy may
leave the C. T. before reaching the 15-yard stretch and approach the
traverse from above or flank. In anticipation of this, the position “H”
is selected slightly in rear and to flank of the traverse, and in this
position one of the automatic rifles may take up, either originally or
by retirement from “E,” and deliver the required traversing covering
fire across the front of “E” and giving adequate protection to the
garrison manning the island-traverse. Barbed wire is also generally
placed in open ground such as this described, say, for instance,
between “K” or “L” on either side of the 15-yard stretches to impede
hostile exit and advance. The overhead traverse just in front of the
island gives protection against bombs thrown down on C. T.
When covering fire is not required, the position “H” will form an
alternative position should the island-traverse be destroyed by shell
fire or taken by the enemy; but the latter will be of little use to
the enemy as their progress passed it is blocked by a loophole placed
at “H” and covering the trench “M” down which they must advance. It
also covers a dummy trench, shown as “N,” down which there is a fair
chance that the enemy would naturally go if a misleading notice were
placed at the junction of “M” and “N.” The slight turn at the end,
“O,” will prevent premature knowledge as to the real nature of this
trench. The enemy’s progress may also be blocked for a short time by
having rolls of looped wire, sometimes known as concertina wire, so
placed in recesses in the side of the trench, and so arranged that when
a man retiring down a trench can catch hold of the roll as he passes
a recess, uncoils it as he runs, leaving it in the trench in a badly
tangled mass.
[Illustration: Section III
SKETCH OF TRENCH SYSTEM]