all, we had drawn upon the enemy's strength so that the French armies were relieved of that amount of resistance to their offensive against the Chemin des Dames. That was the idea behind it all, and it succeeded, though the cost was not light. The battle of Arras petered out into small engagements and nagging fighting when on June 7 the battle of Messines began. It was a model battle, and the whole operation was astonishing in the thoroughness of its preparations through every detail of organization, in the training of its method of attack, in generalship and staff work, and in its Intelligence department. The 2nd Army had long held this part of the Ypres salient, and knew the enemy's country as well as its own. The observers on Kemmel Hill, which looked across to Wytschaete Ridge, had watched every movement in the enemy's lines, and every sign of new defensive work. Aeroplane photographs, stacks of them, revealed many secrets of the enemy's life on this high ground which gave him observation of all our roads and villages in the flat country between Dickebusch and Ypres. A relief map on a big scale was built up in a field behind our lines, and the assault troops and their officers walked round it and studied in miniature the woods and slopes, strong points and trenches, which they would have to attack. For eighteen months past Australian and Canadian miners had been at work below ground boring deep under the enemy's positions and laying charges for the explosion of twenty-four mines. All that time the enemy, aware of his danger, had been counter-mining, and at Hill 60 there was constant underground fighting for more than ten months when men met each other in the converging galleries and fought in their darkness. As Sir Douglas Haig has written, at the time of our offensive the enemy was known to be driving a gallery which would have broken into the tunnel leading into the Hill 60 mines. By careful listening it was judged that if our attack took place on the date arranged, the enemy's gallery would just fail to reach us. So he was allowed to proceed. Eight thousand yards of gallery had been bored, and there were nineteen mines ready charged with over a million pounds of explosives. I saw those nineteen mines go up. The earth rocked with a great shudder, and the sky was filled with flame. It was the signal of our bombardment to break out in a deafening tumult of guns after a quietude in which I heard only the snarl of enemy gas-shells and the shunting and whistling of our railway engines down below there in the darkness as though this battlefield were Clapham Junction. Round about the salient a network of railways had been built with great speed under the very eyes of the enemy, and though he had shelled our tracks and engines he could never stop the work of those engineers who laboured with fine courage and industry so that the guns might not lack for shells nor the men for supplies on the day of attack.