We attacked as usual without a preliminary bombardment and met with a desperate resistance, the German machine-gunners defending their posts with extraordinary heroism, and often firing their guns till the very moment when they and their weapons were crushed to the earth by an attacking Tank. A particularly interesting account of the action is given in the 13th Battalion History-- “It was soon evident that the enemy were prepared to make a stout resistance; there was no definite trench system, but nests of machine-guns were encountered in organised shell-holes almost from the start; while Saint Martin’s Wood and the gully to the east of this, Herleville Wood, and the quarry at its southern end, were all strongly held by machine-guns in prepared emplacements. As before, the German gunners fought with magnificent pertinacity and courage; one Tank Commander claimed to have knocked out over thirty machine-guns, and this claim was supported by the infantry with him; the estimates of several other Tanks were almost as high. These machine-guns were provided with armour-piercing bullets, and Tanks were pitted all over and in many places penetrated by these. There is no doubt that by themselves becoming the targets for these batteries, the Tanks saved many casualties among the infantry. With the machine-guns well in hand, the Australian infantry were quick to seize the chances of advance, and by 6.30 a.m. were all established in their final objectives. After sunrise the heat of the day became oppressive in the open air, and in the Tanks intolerable. Several cases were reported of men becoming delirious during the action. The cause appears to be three-fold: the weather conditions were trying even to fresh men; in many cases the composite crew had recently endured the strain of action without a complete rest to follow; and a third disadvantage, which was inherent in the design of the Mark V. Tank, was now for the first time becoming evident. In these engines the heat generated by the explosion of the propelling gases is very great, and the exhaust pipes speedily become red, and even white hot. In a new engine this is merely an inconvenience, but after a certain period of use the joints of the exhaust pipes tend to warp, and thus to release into the inner air the carbon gases of the explosion. These gases, if breathed continuously, even in small quantities, produce exhaustion, mental confusion and finally unconsciousness. Further, the effect is cumulative, and a man once poisoned by the fumes becomes more quickly affected by further exposure to them. The study of these conditions and the remedy for them became henceforward a matter of the first importance.