Just before the great Vimy Ridge offensive a crowd of us stood on a small hillock beside our camp, which is in a wood six or seven miles behind our lines, to watch the "earthquake" that was to open on Thelus at 3 p.m., and of which we had been told by brigade. The "earthquake" was to take the form of a bombardment of Thelus,—a small town one mile behind the German lines, opposite our front, and which, from the lines, we could see very distinctly with the naked eye,—by every gun of ours that could throw a shell into it. As guns here are much more numerous to the square mile than they were even at the Somme, and as others are going forward day and night, some so large that it takes eight or ten horses to pull them, and as ammunition goes forward at the rate of three or four hundred motor lorries full daily for each mile of front, this means indeed an earthquake.

We stood on the hillock at the "zero" hour, and on the stroke of three, shells began to burst on the skyline. Some, high explosives probably, caused those immense black upheavals of earth which, except for their color, remind one of nothing so much as the spouting of a whale at sea. Others bursting higher in the air, shrapnel very likely, left large, white, fleecy clouds just above the skyline, and a third type burst with a flash of flame, and left brown clouds of smoke in their wake.

Higher in the air, all along the front, some near, some far, some ours, and others the enemy\'s, hung nine immense observation balloons; and soaring in and out among them were twenty-one aeroplanes by actual count at one moment. Some of them were being shelled, for fluffy clouds of smoke were about them showing the bursting shells from anti-aircraft guns, and while we watched two machines engaged in on............