An overpowering heat, as from a vast open furnace, arose from the battlefield below. It was the heat from thousands of explosions, renewed incessantly and sustained over many hours. Stifling gusts blew on to the aviator's face, carrying with them a peculiar smell of burning cloth. With these gusts the roar of the battle seemed to leap up to him. The air was oppressive despite the speed at which he clove it, highly charged with electricity, heavy with the menace of a storm. Yet no cloud broke the monotony of the blue sky. The machine raced onward, was now crossing the battle lines of the enemy's left flank. Suddenly he heard a faint rattle behind him. The hostile aeroplane, realising that it had failed to head him off, was firing furiously. He felt the machine shiver under a quick succession of hard raps. Instinctively, he pressed upon his accelerator, and, with a touch on the warping lever, the machine shot forward at terrific speed. The raps ceased. He turned his head and saw his enemy rapidly diminish in size behind him, saw that the other aeroplane, the one he had seen first, had fallen far in rear. A confident smile came on the tight lips of the aviator. He could outpace them both. He was now above the enemy's left flank--a little to the right of the spot that the Commander-in-Chief had designated as the object of his possible attack. The scout switched off his engine and commenced to drop along a slant towards the centre of the enemy's position. With the sudden silencing of his engine the roar of the battle came up at him in a crash and stayed there. He glanced at the time--12.13--and gave himself a limit of two minutes in which to reconnoitre. For the moment he ignored his adversaries in the air. As he gazed down through the transparent panel between his feet, his glasses to his eyes, the ground that slid away under him appeared to be subjected to a constantly increasing magnification. Fields, houses, roads grew momentarily more distinct. Without taking his gaze from the scene below the aviator checked the drop of his machine and drove forward. Quickly his trained eye took in the details of the ground, the position and approximate numbers of the men that he saw massed in dark patches here and there. Over a long stretch of the position the enemy's line was obviously thinner. The country behind it was empty of troops. The General's intuition was correct. The enemy had weakened his left centre. Point Number One was settled. Now what had he done with the troops he had withdrawn?