Y Ravine at Beaumont Hamel) this
trip-wire was used with thin iron spikes a yard long of the kind known
as calthrops. The spikes were so placed in the ground that about one
foot of spike projected. The scheme was that our men should catch
their feet in the trip-wire, fall on the spikes, and be transfixed.

In places, in front of the front line in the midst of his wire,
sometimes even in front of the wire, the enemy had carefully hidden
snipers and machine-gun posts. Sometimes these outside posts were
connected with his front-line trench by tunnels, sometimes they were
simply shell-holes, slightly altered with a spade to take the snipers
and the gunners. These outside snipers had some success in the early
parts of the battle. They caused losses among our men by firing in the
midst of them and by shooting them in the backs after they had
passed. Usually the posts were small oblong pans in the mud, in which
the men lay. Sometimes they were deep narrow graves in which the men
stood to fire through a funnel in the earth. Here and there, where the
ground was favourable, especially when there was some little knop,
hillock, or bulge of ground just outside their line, as near
Gommecourt Park and close to the Sunken Road at Beaumont Hamel, he
placed several such posts together. Outside Gommecourt, a slight
lynchet near the enemy line was prepared for at least a dozen such
posts invisible from any part of our line and not easily to be picked
out by photograph, and so placed as to sweep at least a mile of No
Man's Land.

[Illustration: Sleighs used for conveying the Wounded through the
Mud]

When these places had been passed, and the enemy wire, more or less
cut by our shrapnel, had been crossed, our men had to attack the enemy
fire trenches of the first line. These, like the other defences,
varied in degree, but not in kind. They were, in the main, deep, solid
trenches, dug with short bays or zigzags in the pattern of the Greek
Key or badger's earth. They were seldom less than eight feet and
sometimes as much as twelve feet deep. Their sides were revetted, or
held from collapsing, by strong wickerwork. They had good,
comfortable standing slabs or banquettes on which the men could stand
to fire. As a rule, the parapets were not built up with sandbags as
ours were.

In some parts of the line, the front trenches were strengthened at
intervals of about fifty yards by tiny forts or fortlets made of
concrete and so built into