heavily fortified barrier to bar the Allied advance between Ypres and
Armentiers. Since December, 1914, the Germans had seamed the western
slopes with trenches, a network of tunnels and of concrete redoubts.
Behind the ridge lay the German batteries. For months this ridge had
been mined and countermined by both sides, until the English had placed
500 tons of high explosive, that is approximately 1,000,000 pounds of
amminol, beneath nineteen strategic points which were to be taken. At
the foot of the ridge, along a front of nine miles, the British had
concentrated their batteries, heavy guns, and vast supplies of
ammunition. Day and night for a week before the battle began, the
German positions had been shelled. At times the hurricane of fire died
down, but it never ceased. By day and by night the German trenches
were raided and explored. A large fleet of tanks was ready for the
advance. Hundreds of aviators cleared the air and dropped bombs upon
the enemy, assailing his ammunition dumps, aerodromes, and bases of
supplies. The battle had to be fought simultaneously by all the forces
on the land, in the air, and in the mines underground. All the horrors
of the cyclone and the earthquake were harnessed for the conflict.

In the early morning, a short, deathly silence followed the week's
terrific bombardment. At 2:50 a. m. the ground opened from beneath, as
nineteen great mines were exploded one by one, and fountains of fire
and earth like huge volcanoes leaped into the air. Hill 60, which had
dealt such deadly damage to the British, was rent asunder and
collapsed. It was probably the greatest explosion man ever heard on
earth up to that time. Then the guns began anew to prepare for the
attack and a carefully planned barrage dropped just in front of the
English battalions as they advanced. As the men came forward, the
barrage was lifted step by step and dropped just ahead of them, to
pulverize the enemy and protect the British troops. By five o'clock