But the pushpot sabotage—and Joe was sure it was nothing else—was not that sort of thing. Making motors explode.... Motors don’t explode. One couldn’t put bombs in them. There wasn’t room. The explosions Joe had seen looked as if they’d centered in the fire basket—technically the combustion area—behind the compressor and before the drive vanes. A jet motor whirled. Its front vanes compressed air, and a flame burned furiously in the compressed air, which swelled enormously and poured out past other vanes that took power from it to drive the compressor. The excess of blast poured out astern in a blue-white flame, driving the ship.

But one couldn’t put a bomb in a fire basket. The temperature would melt anything but the refractory alloys of which a jet motor has to be built. A bomb placed there would explode the instant a motor was started. It couldn’t resist until the pushpot took off. It couldn’t....

This was a different kind of sabotage. There was a different mind at work.

In the afternoon Joe watched the landings, while the young lieutenant followed him patiently about. A pushpot landing was quite unlike the landing of any other air-borne thing. It came flying down with incredible clumsiness, making an uproar out of all proportion to its landing speed. Pushpots came in with their tail ends low, crudely and cruelly clumsy in their handling. They had no wings or fins. They had to be balanced by their jet blasts. They had to be steered the same way. When a jet motor conked out there was no control. The pushpot fell.

He carefully watched one landing now. It came down low, and swung in toward the field, and seemed to reach its stern down tentatively to slide on the earth, and the flame of its exhaust scorched the field, and it hesitated, pointing up at an ever steeper angle—and it touched and its nose tilted forward—and leaped up as the jet roared more loudly, and then touched again....

The goal was for pushpots to touch ground finally with the whole weight of the flying monstrosity supported by the vertical thrust of the jet, and while it was moving forward at the lowest possible rate of speed. When that goal was achieved, they flopped solidly flat, slid a few feet on their metal bellies, and lay still. Some hit hard and tried to dig into the earth with their blunt noses. Joe finally saw one touch with no forward speed at all. It seemed to try to settle down vertically, as a rocket takes off. That one fell over backward and wallowed with its belly plates in the air before it rolled over on its side and rocked there.

The last of a flight touched down and flopped, and the memory of the wreckage had been overlaid by these other sights and Joe could think of his next meal without aversion. When it was evening-mess time he went doggedly back to the mess hall. There was a sort of itchy feeling in his mind. He knew something he didn’t know he knew. There was something in his memory that he couldn’t recall.

Talley and Walton were again at mess. Joe went to their table. Talley looked at him inquiringly.

“Yes, I saw both crashes,” said Joe gloomily, “and I didn’t want any lunch. It was sabotage, though. Only it was different in kind—it was different in principle—from the other tricks. But I can’t figure out what it is!”