"Sit down," ordered Billy, and grasping his comrade by the nape of the neck he bent his head until it rested on his knees. "Keep like that a while," he continued. "I'll get rid of incriminating evidence. My word, what a lump!" he added, as he lifted the dead brute by its hind legs. "Half a hundredweight, I should imagine." Keeping the carcass clear of the ground the flight-sub carried it quite fifty yards through the wood before depositing it under a bush. This necessary task performed, he retraced his steps. "Chirpy again?" he inquired. "Quite," replied Kirkwood. "You look jolly warm," continued Barcroft. "I feel it." "Then get a move on and swarm up here," interrupted Fuller's voice. "I'm as cold as charity and could do with a human warmingpan. "All clear?" inquired Barcroft. "By Jove, no!" was Fuller's hurried rejoinder. "Look sharp, you fellows. There are half a dozen of 'em coming this way." Making sure that they had left behind them no evidence of their presence the two airmen re-ascended to their lofty perch. "You're steaming like an overworked horse, old man," said Billy addressing the A.P. "I'll throw your coat over you. You can't sit up or the Fritzes will spot us." Trudging across the tilled land were eight or nine greatcoated Huns, armed with rifles. Two of their number were drawing a light cart. "What's that for, I wonder?" whispered Kirkwood, for the Germans were still a considerable distance off, yet making almost in a straight line for the tree in which the three chums were hidden. "Can't say," replied Fuller. "I never saw Huns with a contraption like that before. Rations, possibly: they may mean to camp out here just to keep us company." The fugitives were not left long in doubt, for on arriving at a spot twenty yards from the edge of the wood the party halted and proceeded to don flexible metallic masks with hideous-looking snouts. This done, the corporal in charge inspected each man's face-protection with deliberate thoroughness, while from a distance two Hun officers in the uniform of the Engineers watched the proceedings. "By smoke!" muttered Barcroft under his breath. "They're going to have a shot at gassing us." At a brisk order the lid of the cart was thrown back revealing a couple of cylinders to which were attached lengths of armoured metallic hosepipe terminating in elongated nozzles. First the cylinders were placed upon the ground and air pumped into them until the required pressure was obtained. Then each apparatus was strapped to a man's back, a soldier being in attendance to hold the nozzle. It was fairly safe for the three British officers to watch the proceedings since the height of the branch enabled them to look down upon the heads of the gassing party, while the latter could not look up owing to the straps that secured the lower portion of their masks to their shoulders. "Reminds me of goblins at a panto," thought Bobby. "Wonder when they're going to start?"