Then suddenly on a mighty breadth of line spoke the guns, came the swift chasing shells through the sky, and the chorus of their sighs and their cat-calls and yells and the hubbub of disruption in their explosion. Trench mortars of all calibres and field-guns had been brought up to closest range under cover of mist and darkness, and pounded into all our trenches thick and warm with khaki and live flesh and blood, and from behind the field-guns, but not far behind, in serried ranks spoke the heavy guns, the Russian heavies, the Italian heavies, the grand Austrian heavies, heaving death and destruction in the paths of retreat. Accommodated with the heavies in fiendish fraternal task were the light guns in vast numbers which flung the gas-bombs in tens of thousands to the spots where of a certainty there must be congestion of traffic in the British rear. It was ten minutes to five in the morning of the 21st March--_der Tag_ had come, the hour of German fate had struck. Our guns replied at once in mighty salvos from accustomed points on the horizon, but also many hitherto silent guns and batteries spoke for the first time. A steady and perhaps unimaginative confidence was expressed by our artillery, but it was quickly realised that we were out-gunned and out-manned. Our battery positions were soon drenched with mustard gas. The enemy firing was remarkably accurate and scored direct hits on many headquarters, billets, and ammunition dumps which had never been assailed before. The roads all received a great deal of attention and at many vital points deep craters threatened to hold up traffic for hours.