The Messines ridge is a long, low hill, only about 300 feet in height, but it commands the countryside for miles around, and had become the 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 Messines itself was captured by the fearless Australians. There was a most desperate struggle just here where we were standing at Wytschaete. All morning the battle raged along this line, but by midday it was in the hands of the dashing Irish division. Seven thousand prisoners were taken, while the British casualties, owing to the effective protection of their terrific barrage, were far less than the German and only one-fifth of what they had calculated as necessary to take this strategic position.