Suddenly in the midst of the task of inflating the collar Kirkwood removed the tube from his lips. The air rushed out, and the rubber fabric collapsed like a punctured pneumatic tyre, while the A.P. stared with wide-open eyes at something not more than a hundred yards distant above the surface of the water.
"A periscope, by Jove!" he exclaimed, making a grab at his maps and papers. They, at all events, had to be destroyed.
Although his companion heard not a sound his attention was attracted by Kirkwood's manner. He, too, saw the spar-like object forging slowly ahead—so slowly that the cleavage of the water was insufficient to throw up the usual tell-tale feather of spray.
Deliberately, almost human-like, the eye of the periscope turned slowly in a complete circle. The submarine, satisfied that there was no immediate danger to be anticipated, shook herself clear of the water, disclosing her conning-tower and a portion of the hull of one of the British G Class.
Hardly able to credit their good fortune the flight-sub and his companion thrust their maps into their pockets and began to wave for assistance a quite unnecessary act since the lieutenant-commander of G 21 had already concluded rightly that the airmen were his compatriots in distress.
Five or six of her crew appearing on the long, narrow deck, the ungainly hull of the submarine, skilfully manoeuvred, approached sufficiently close to enable Kirkwood to catch a coil of rope, and the seaplane was hauled alongside.
"Jump, sir!" shouted a petty officer.
Although unable to hear the words Barcroft understood the gesture. He waited until his observer had leapt, then seizing a small axe from the body of the fuselage, he shattered each of the frail floats, and as his command sank beneath his feet he scrambled up the bulging side of the rescuing submarine.
"Barcroft's deaf and dumb," Kirkwood explained to a sympathetic lieutenant. "You'd better look sharp. There are a dozen strafed torpedo-boats after us."
"P'raps it's as well if we do," commented the officer. "I'll trouble you for your yarn when we are snugly down below."