But more particularly crews had had proper time to train and they knew that they knew their work. Their officers, too, were sure that they would this time be properly supplied with maps and detailed orders. Therefore, officers and crews got on with their own battle preparations, or, later, rehearsed the coming action with the infantry, with a good heart. II In the front line active preparations had begun. The Reconnaissance Officers, several of whom took up their quarters in the half-deserted town of Arras, had each had his area allotted to him, and they were busy helping “Q” side to find suitable positions for the supply dumps, for at this time there was no system of supply Tanks. Every tin of petrol, every round of ammunition, had, therefore, to be carried by hand from the railhead, and the task was one which took weeks to complete. It was calculated that had supply Tanks been available each machine would have saved a carrying party of 300 men. The real work of the Reconnaissance Officers, however, was to observe the enemy’s lines and the country which lay beyond them. Much of this country, even within our own lines, was practically unknown to us, as the greater part of the sector selected for attack had only just been “uncovered” by the sudden and unforeseen German retirement. On this portion of the line the retirement had occurred about a month before the battle was due. As in other parts of the line, and as the enemy had intended, the retirement had proved extremely embarrassing. We had carefully selected a site for our battle, and the chosen ground had been thoroughly studied. The sudden change to a piece of imperfectly known country involved an enormous amount of extra photographing, map-making, sketching and reconnaissance generally. This was merely troublesome; more uncomfortable was the element of uncertainty which the retirement introduced. Would the enemy stand? And, if so, where? Was there some trap being prepared for us? It was uncanny, for it was contrary to the tradition of more than two years of trench warfare. The final scheme of the attack was, however, planned on the assumption that the enemy would give battle. For he now held a line of great natural strength which he had improved with extraordinary skill and energy. The scheme, as it affected the Tanks, was shortly this. The general object of the action was to achieve a rapid success. That is, to inflict a wound in the first twenty-four hours, severe enough to force the enemy to bring up his reserves, thus depleting his line near Soissons and Reims, where the French offensive was to be launched immediately afterwards. A proportion of Tanks was allotted to each of the Armies taking part. 1. _With the First Army_ (“D” Battalion) to the North: