A second dark cloud swept forward in the gathering dusk and merged into the mass of fliers about the dome. Five minutes later, a third. Dense as the air-traffic was, riding-lights were necessary. They began to appear in the deepening twilight. It seemed as if all the sky were alight with fireflies, whirling and swirling and fluttering here and there. But then the fire-drill began to emit a tiny wisp of smoke. Thorn worked furiously. Then a tiny flickering flame appeared, which he nursed with a desperate solicitude. Then a larger flame. Then a roaring blaze! It could not be missed! A fire within the dome could not fail to be noted and examined instantly!
A searchlight beam fell upon them, illuminating him in a pitiless glare. Thorn waved his arms frantically. He had nothing with which to signal save his body. He flung his arms wide, and up, and wide again, in an improvised adaption of the telegraphic alphabet to gesticulation. He sent the watch call over and over again....
A little cloud of riding-lights swept toward the dome from an infinite distance away. Darkness was falling so swiftly that they were still merely specks of light as they swept up to and seemed to melt into the swirling, swooping mass of fliers about the dome....
Cold sweat was standing out on Thorn's face, despite the violence of his exertions. He was even praying a little.... And suddenly the searchlight beam flickered a welcome answer:
"W-e u-n-d-e-r-s-t-a-n-d. R-e-p-o-r-t."
Thorn flung his arms about madly, sending:
"G-e-t a-w-a-y q-u-i-c-k. C-o-m P-u-b-s h-e-r-e. W-i-l-l m-a-k-e o-t-h-e-r d-o-m-e o-u-t-s-i-d-e t-o t-r-a-p y-o-u."
The searchlight beam upon him flickered an acknowledgment. He knew what was happening after that. The G.C. phones would flash the warning to every ship, and every ship would dash madly for safety.... A sudden, concerted quiver seemed to go over the whirling maze of lights aloft. A swift, simultaneous movement of every ship in flight. Thorn breathed an agonized prayer....
There was a flash of blue light. For one fractional part of a second the stars and skies were blotted out. There was a dome of flame above him and all about the world, of bright blue flame which instantly was—and instantly was not!