"Those fellows will give a good account of themselves, I guess," remarked Kaye. "Sometimes, old thing, I almost wish that I were in the infantry." "They get all the kicks," rejoined Daventry. "Our guns start strafing the Boche. Boche gets angry and starts to shell back. Shell what? Not our guns so much as the poor beggars of infantry in the trenches. They always get it in the neck." "All the same, I envy 'em," continued Kaye. "We don't get a chance of surging over the top in a yelling, cheering mob. That's life, if you like. Were you ever in the neighbourhood of Courcelette? If---- Hallo! What's this? A Boche?" High over--three thousand feet--a large German biplane was circling as if looking for a quarry. The Hun was alone, for practically every available machine was up and away from the aerodrome. Either the hostile airman was engaged in taking aerial photographs of the "back areas", or else he had spotted the battalion moving slowly in column of route. The troops were fully aware of the undesirable presence of the Boche airman, and now came a test of discipline. It was one of those occasions when a British soldier must not look danger in the face, for a quadruple line of upturned faces would be clearly visible to the Hun pilot, while the battalion might escape notice by keeping their heads bent down. Derek and his companion remained perfectly still, taking doubtful cover under a gaunt tree. From where they stood they could watch practically the whole of the now motionless column. Officers and men, although tempted to see what was going on up above, were standing rigid, not knowing whether a bomb might scatter wounds and death amongst the compact crowd of troops. "Good heavens!" whispered Derek, although there was not the slightest reason why he should have lowered his voice. "I believe Fritz has spotted the column. He's coming down to make sure." "You're right, old man, I think," agreed Kaye. "There'll be an unholy mess of things in----" Bang. A violent concussion almost deafened the two airmen. It was only a paramount feeling that the Tommies might roar at them that prevented Derek and his companion from throwing themselves flat upon the ground. Turning, they heard the metallic clang of a breech-block being swung home, and were just in time to see the long pole-like chase of an anti-air-craft gun rise from a cleverly camouflaged pit not twenty yards from where they stood. There was no need for a second shot. The shell from the "anti" burst with mathematical precision right in front of the black-crossed aeroplane, and the next instant the machine began to fall earthwards. It was not until the enemy biplane crashed that the Tommies were aware of the turn of events, and a roar of cheering burst from eight hundred throats. "Pretty shot that," remarked Kaye approvingly. "Hanged if I knew that there was an A.A. battery about here."