Just then Tom gave his chum a kick with the toe of his shoe. This suddenly reminded Jack that he was treading on forbidden ground, since they had resolved not to say anything to a third person concerning the adventure of that afternoon.
The other member of the escadrille was looking interested. He understood that Tom and Jack must have met with some singular adventure; but since they did not see fit to take him into their confidence he was too polite to ask questions, feeling there must be a good reason for their silence.
Presently they arrived at the hangars. It was now almost sunset. The fliers were coming down one by one, their labor for the day having been accomplished. It had been a pretty arduous day, too, and two members of the escadrille had new honors coming to them, since they had dropped enemy planes in full view of tens of thousands of cheering spectators, after thrilling combats high in the air.
One had also passed through an experience that few aviators can look back to. He had started to drop rapidly when, at almost ten thousand feet altitude, his motor was struck by a missile from a rival pilot's gun. When halfway down, either through a freak of fortune or some wonderfully clever manipulation on the part of the pilot, the machine righted, and he was enabled to volplane to safety, though considerably bruised and cut up through hasty landing.
Jack quickly had his little Nieuport out of the hangar, and the three airmen began a minute inspection. For a short time nothing developed that had a suspicious appearance. Jack, in fact, was beginning to believe the warning might after all be in the nature of a fake, or else the spy had not found a favorable chance to do his foul work before being frightened off.
But presently Tom gave utterance to an exclamation.
"Found anything, Tom?" asked Jack eagerly.
"Yes. Come around here, both of you!"
When the others joined Tom he pointed to where an important wire stay had been dextrously filed so that it must snap under a severe wrench or strain, such as commonly comes when a pilot is far afield, and wishes to execute a necessary whirl.
Jack shivered as he took in the meaning of that partly severed stay. If it gave way while he was far above the earth it must spell his certain doom!