field guns, at the earliest possible moment. Materials for this were, of course, prepared in advance, as were some for a minor bridge, for infantry and pack transport, to be thrown across at a suitable point some fifteen hundred yards further south. A glance at the map[44] will show that the German defences west of the Canal began at the northern spoil heap, consisted for the greater part of their length up to the Bapaume-Cambrai Road of two main lines, and at their greatest depth, on a frontage of fifteen hundred yards, of three. No tanks were allotted to the 36th Division, so a frontal attack without artillery preparation was out of the question. It was decided, therefore, to capture the northern spoil heap, wire in front of which had been cut over a long period by artillery and a 6-inch trench mortar with instantaneous fuse--the latter the best wire-cutter the 36th Division ever discovered--and work up the trenches from south to north. It appeared that this sixty-foot pile would enable machine and Lewis guns to cover the infantry in their advance. On paper the task of working up these trenches, traversed at frequent intervals by rays of wire, appeared of well-nigh insuperable difficulty. And, indeed, no planning and no gallantry in execution could have accomplished it had not the enemy troops been much demoralized by the advance of the tanks behind them east of the Canal, as it was intended they should be. The attack of the 36th Division was, therefore, not to take place till the main attack had drawn level with its point of departure. Zero for the former was at 6-20 a.m.; for the 36th Division at 8-35 a.m.