ons of the fire-fight are likely to be favourable, it is
probably better to accept the inevitable casualties that must result from
a struggle for fire supremacy, rather than adopt the undoubted hazards of
a night assault." These conditions are frequently so unfavourable in
Position Warfare, owing to the strength of consolidated positions and to
the increasing accuracy and density of artillery fire, that assaults are
made of necessity in the hours of darkness, in preference to those of
daylight. During the _Battle of the Somme_ (July 1-17, 1916) a night
advance was made by seven divisions on a front of about 4 miles. The
troops moved out in the early hours of July 14, for a distance of about
1,400 yards, and lined up in the darkness below a crest some 300 to 500
yards from the enemy's trenches. Their advance was covered by strong
patrols and their correct deployment had been ensured by white tapes laid
out on the ground earlier in the night of July 13-14. The whole movement
was carried out unobserved and without touch being lost in any case. The
assault was delivered at 3.25 a.m., when there was just sufficient light
to be able to distinguish friend from foe at short range, and along the
whole front attacked the troops were preceded by an effective artillery
barrage. They swept over the enemy's first-line trenches and
consolidated their position in the defences beyond.

On the night of February 10-11, 1917, the 32nd Division attacked and
captured 1,500 yards of trench {149} line at the foot of the _Serre
Hill_. The division formed up after dark and the attack began at 8.30
p.m., the objective was captured, and at 5 a.m. a determined
counter-attack was repulsed. The capture of the _Vimy Ridge_ by Canadian
troops was due to an assault launched some time before dawn on April 9,
1917: and the British victory of Messines (June 7, 1917) to an assault
launched at 3.10 a.m. In the latter case the Wytschaete-Messines
position, "one of the Germans' most important strongholds on the Western
Front, consisted of forward defences with an elaborate and intricate
system of well-wired trenches and strong points, forming a defensive belt
over a mile in depth, and the Germans had omitted no precautions to make
the position impregnable" (Sir D. Haig's Dispatches). Nineteen deep
mines under this position were fired at 3.10 a.m., and this was the
signal for the assault, which was immediately successful and was carried
out under inte