Burke immediately closed the switch that started the elevating motor, and slowly the huge cylinder turned on its trunnions like a siege-mortar. In the control-room, Atterbury stood at the great copper switch, the closing of which would throw the full force of the current into the coils and liberate the ray.
The moment had at last arrived for the electrocution of Medusa—the crucial moment of their journey! In spite of their seeming nonchalance, there was not one of the four but felt his pulses quicken at the realization that on the result of the movement of Atterbury’s right hand depended the continuance of human life upon the earth. They looked at one another mutely. Then Bennie smiled a curious, hesitating smile, and turned from the window through which he was watching the asteroid.
" ’You may fire when ready, Gridley!' ’’ he shouted.
Framed in the doorway of the control-room, Rhoda saw Atterbury throw over the switch, and heard the hum of the alternating current in the coils of the inductor.
For a minute—two minutes—nothing happened; then the outer shell of the inductor turned a dull red, glowed brighter, and rose to white heat. They observed no ray; yet even then the ray was traveling out into the abyss of space. They had seen but the "smoke of the discharge." A sudden flash of light burst like a bomb a little to one side of the asteroid.
"Low and to the left!" yelled Bennie. "But we caught a meteorite! It passed through the ray and exploded."
Gives me the direction," nodded Burke. "R-3.
He pressed a small button, closed a second switch, and the cylinder outside swung slowly on its vertical axis. Almost instantly, a misty splash of yellow fire appeared upon the dark side of the asteroid and shot off into space.
"Hit!" cried Bennie. "Hold it, Burke; hold it! Rhoda, don’t miss that!"
Gradually, the luminous discharge from Medusa increased in brilliancy until the planet became a ball of fire. Giant sheets of yellow light, like aurora streamers, drove off from its surface as the deadly ray bored against it until the asteroid resembled a vast volcanic eruption. Under the fierce blast from the Ring, its surface was melting away, and driving out into space a glowing mass of incandescent gas. Burning thus, out in the blackness of space, it resembled a conflagration—the burning-up of a powder factory—seen at a safe distance through the night.
A safe distance? Unexpectedly, out of the darkness, a shower of moving points of light appeared in the ether, around the asteroid, darting hither and yon, growing larger momentarily as, shining in the light of the sun, they traced luminous lines across the sky. Medusa was returning the attack! The explosions upon the planet's surface were hurling great fragments of rock and stone in every direction, filling space with flaming missiles, contact with the smallest of which meant death to the dating voyagers in the Ring. Several of these molten fragments hurtled by the windows, blazing fiercely but making no sound, while some, encountering others in their flight, exploded silently, like distant rockets breaking in the zenith.
Everywhere the heavens were a mass of shooting-stars of every conceivable color—green, purple, blue, orange, yellow, red, and lilac—a kaleidoscopic display of surpassing beauty, of fearful wonderment. It was as if some demigod had emptied a furnace into the heavens, scattering its glowing contents throughout the sky, or as if a million bombs at pointblank range were bursting on every side and discharging showers of fireworks about the Ring. But already Medusa had commenced her retreat, already her disk appeared smaller, and to prolong the bombardment meant only unnecessary danger to the occupants of the car.
"I guess we’ve given her ’what for,' ” commented Burke. "She’s running away from us. Shall we let up?”
Bennie signaled to Atterbury to throw off the current, and the conflagration on the asteroid ceased as suddenly as it had started. The volcanic bombs continued to fly by them at occasional intervals, but presently the last one passed, and they breathed freely again. They had escaped. Their work was done. The earth was saved. They could return.
II
"They could return.” How easy to say the words—as easy as it had been to fly off by means of their radioactive power from the surface of the earth! But, now that the necessity of returning whence they had come presented itself, they suddenly realized difficulties which had hitherto not suggested themselves. While they had paralleled the course of Medusa, they had been headed straight for the earth, which hung in the sky above them, a gigantic crescent of a dazzling bluish white, its oceans and continents barely discernible through the haze of its atmosphere.
Even as they watched it, they could observe its rotation as one can detect the movement of the minute-hand of a clock. The moon had presented no such problem. It was dead, almost without axial motion. But the earth was very much alive, whirling on its axis with a speed at the equator of a thousand miles an hour— nearly that of a shell from a rifled cannon. How could they land upon it? Theirs seemed to be the superhuman task of the clown who tries to climb upon the revolving table at the circus—an impossibility. When they had left the earth, they had assimilated this axial motion, and, in steering their course through the ether, they had allowed for it, as the navigator allows for the tide or the set of the current. But now, on their arrival at the globe’s surrounding atmosphere, they would be attempting to land upon a ball revolving with a velocity of ten or fifteen times that of the fastest express-train.
"We could land at either of the poles," suggested the research professor. "Of course there wouldn’t be any motion there!"
"Yes; we might do that," agreed Bennie; "or" - and he scratched his head—"we can navigate the Ring toward the earth in a spiral orbit. Anyhow, the Ring has got to follow the earth in
her orbit around the sun."
"There’s something funny about it," interrupted Burke. "Suppose you started at the poles and drove the Ring toward the equator, how would you keep up with the increasing surface-velocity of the earth?"
"Why," answered the master of the Ring, "it’s the—the—let me see—it must be the atmosphere that would drive you eastward all the time."
"Of course!" exclaimed Rhoda. "What a lot of sillies we are! It’s perfectly simple. You don’t need any spiral orbits or anything else. All you’ve got to do is to bring the Ring down into the upper atmosphere and hover at a fixed elevation until we are swept along at the full speed of the earth."
Burke, who was lighting his pipe, paused and pursed his lips.
"Wouldn’t we be coming down into a terrific wind?" he inquired, "Fourteen hundred feet a second! My word! Some blow!"
"Depends on the latitude, of course," answered Bennie. "We’ve got to run around the earth as we descend, or else we’ll be on the dark side—that is, the night side—when we land. Believe me, I want light for that!"
Quite right!" agreed Atterbury, who had joined the group. Just look at the earth now, will you?"
They all craned their necks to follow his gesture. Through the observation-window, the shining crescent of the globe seemed to fill the whole sky. Burke pressed the control-lever, and they swung leftward, boring through space toward the invisible black wall where the earth’s shadow reached out among the stars. Nearer and nearer it drew, then—darkness. Steering by the steady gleam of the friendly planets, as a coasting steamer steers by the distant bead of light that marks the headland, the Ring soared on, bursting at length into full sunlight again.
They were now comparatively close above the earth and, in going around it, had gained the incidental advantage of having acquired the velocity of the planet in its journey around the sun. Only the problem of descent remained. But it was the most serious of all their problems—how to lower themselves in safety into that swirling, boiling mass of vapor that was shooting by so fast as to seem little more than a hideous blur, and left them sick and dizzy at the sight of it.