He listened--listened--to a silent receiver: silent save for the sound of a shot--a crashing fall--a loud, panting breath. He heard the breathing close to the distant instrument; it ended in a choking gasp; the instrument was silent in his ear.... He signalled violently for the operator: ordered the ringing of any and all phones about the observatory, and listened in vain for a sound or syllable in reply. "A plane," he told an orderly, "at once! Phone the commercial flying field near the base of Mount Lawson. Have them hold a car ready for me: I shall land there!" CHAPTER V To Captain Blake alone, of all those persons on the summit of Mount Lawson, it was given to see and to know and be able to relate what transpired there and in the air above. For Blake, although he appeared like one dead, was never unconscious throughout his experience. Driving head on toward the ship, he had emptied his drum of cartridges before he threw his plane over and down in a dive that escaped the onrush of the great craft by a scant margin, and that carried him down in company with the men and machines of the squadron that dived from above. He turned as they turned and climbed as they climbed for the advantage that altitude might give. And he climbed faster: his ship outdistanced them in that tearing, scrambling rush for the heights. The squadron was spiraling upward in close formation with his plane above them when the enemy struck. He saw that great shape swing around them, terrible in its silent swiftness, and, like the others, he failed to realize at first the net she was weaving. So thin was the gas and so rapid the circling of the enemy craft, they were captured and cut off inside of the gaseous sphere before the purpose of the maneuver was seen or understood. He saw the first faint vapor form above him; swung over for a steep bank that carried him around the inside of the great cage of gas and that showed him the spiraling planes as the first wisps of vapor swept past them. He held that bank with his swift machine, while below him a squadron of close-formed fighting craft dissolved before his eyes into unguided units. The formations melted: wings touched and locked; the planes fell dizzily or shot off in wild, ungoverned, swerving flight. The air was misty about him; it was fragrant in his nostrils; the world was swimming.... * * * * * It was gas, he knew, and with the light-headedness that was upon him, so curiously like that of excessive altitudes, he reached unconsciously for the oxygen supply. The blast of pure gas in his face revived him for an instant, and in that instant of clear thinking his plan was formed. He threw his weight on stick and rudder, corrected the skid his ship was taking, and, with one hand holding the tube of life-giving oxygen before his face, he drove straight down in a dive toward the earth.