property of dispersing the sea fogs. There, at rest upon what resembled nothing so much as iron claws, the long gray shape of the vacuum flyer bulked.
Nat sneezed as he watched the operations of his men, for the common cold, or coryza, seemed likely to be the last of the germ diseases that would yield to medical science, and he had caught a bad one in the Capitol, while listening to the debate in the Senate upon the threat to humanity. And it was cold on the landing-stage, in contrast to the perpetual summer of the glass-roofed city below.
But Nat forgot the cold as he watched the preparations for the ship's departure. Neon and nitrogen gas were being pumped under pressure into the outer shell, where a minute charge of leucon, the newly discovered element that helped to counteract gravitation, combined with them to provide the power that would lift the vessel above the regions of the stratosphere.
In the low roof-buildings that surrounded the stage was a scene of tremendous activity. The selenium discs were flashing signals, and the radio receivers were shouting the late news; on the great power boards dials and light signals stood out in the glow of the amylite tubes. On a rotary stage a thousand feet above the ship a giant searchlight, visible for a thousand miles, moved its shaft of dazzling luminosity across the heavens.
Now the spar-aluminite outer skin of the ship grew bright with the red neon glare. Another ship, from China, dropped slowly to its stage near by, and the unloaders swarmed about the pneumatic tubes to receive the mail. The teleradio was shouting news of a failure of the Manchurian wheat crop. Nat's chief officer, a short cockney named Brent, came up to him.
"Ready to start, Sir," he said.
Nat turned to him. "Your orders are clear?"
"Yes, Sir."
"Send Benson here."
"I'm here, Sir." Benson, the ray-gunner in charge of the battery that comprised the vessel's armament, a lean Yankee from Connecticut, stepped forward.
"You know your orders, Benson? Axelson has seized the Moon and the gold-mines there. He's planning to obliterate the Earth. We've got to go in like mad dogs and shoot to kill. No matter if we kill every living thing there, even our own people who are inmates of the Moon's penal settlement, we've got to account for Axelson."
"Yes, Sir."
"We can't guess how he got those gold-ships that returned with neon and argon for the Moon colonists. But he mustn't get us. Let the men understand that. That's all."
"Very good, Sir."
The teleradio suddenly began to splutter: A-A-A, it called. And instantly every sound ceased about the landing-stage. For that was the call of Axelson, somewhere upon the Moon.
"Axelson speaking. At the next full moon all the American Province of the World Federation will be annihilated, as the Chinese Province was at the last. There's no hope for you, good people. Send out your vacuum liners. I can use a few more of them. Within six months your world will be depopulated, unless you flash me the signal of surrender."
Would the proud old Earth have to come to that? Daily those ominous threats had been repeated, until popular fears had become frenzy. And Nat was being sent out as a last hope. If he failed, there would be nothing but surrender to this man, armed with a super-force that enabled him to lay waste the Earth from the Moon.
Within one hour, those invisible, death-dealing rays had destroyed everything that inhaled oxygen and exhaled carbon. The ray with which the liner was equipped was a mere toy in comparison. It would kill at no more than 500 miles, and its action was quite different.
As a prelude to Earth's surrender, Axelson demanded that World President Stark and a score of other dignitaries should depart for the Moon as hostages. Every ray fortress in the world was to be dismantled, every treasury was to send its gold to be piled up in a great pyramid on the New York landing-stage. The Earth was to acknowledge Axelson as its supreme master.
The iron claws were turning with a screwlike motion, extending themselves, and slowly raising the interplanetary vessel until she looked like a great metal fish with metal legs ending with suckerlike disks. But already she was floating free as the softly purring engines held her in equipoise. Nat climbed the short ladder that led to her deck. Brent came up to him again.
"That teleradio message from Axelson – " he began.
"Yes?" Nat snapped out.
"I don't believe it came from the Moon at all."
"You don't? You think it's somebody playing a hoax on Earth? You think that wiping out of China was just an Earth-joke?"
"No, Sir." Brent stood steady under his superior's sarcasm. "But I was chief teleradio operator at Greenwich before being promoted to the Province of America. And what they don't know at Greenwich they don't know anywhere."
Brent spoke with that self-assurance of the born cockney that even the centuries had failed to remove, though they had removed the cockney accent.
"Well, Brent?"
"I was with the chief electrician in the receiving station when Axelson was radioing last week. And I noticed that the waves of sound were under a slight Doppler effect. With the immense magnification necessary for transmitting from the Moon, such deflection might be construed as a mere fan-like extension. But there was ten times the magnification one would expect from the Moon; and I calculated that those sound-waves were shifted somewhere."
"Then what's your theory, Brent?"
"Those sounds come from another planet. Somewhere on the Moon there's an intercepting and re-transmitting plant. Axelson is deflecting his rays to give the impression that he's on the Moon, and to lure our ships there."
"What do you advise?" asked Nat.
"I don't know, Sir."
"Neither do I. Set your course Moonward, and tell Mr. Benson to keep his eyes peeled."
The Moon Colony, discovered in 1976, when Kramer, of Baltimore, first proved the practicability of mixing neon with the inert new gas, leucon, and so conquering gravitation, had proved to be just what it had been suspected of being – a desiccated, airless desolation. Nevertheless, within the depths of the craters a certain amount of the Moon's ancient atmosphere still lingered, sufficient to sustain life for the queer troglodytes, with enormous lung-boxes, who survived there, browsing like beasts upon the stunted, aloe-like vegetation.
Half man, half ape, and very much unlike either, these vestiges of a species on a ruined globe had proved tractable and amenable to discipline. They had become the laborers of the convict settlement that had sprung up on the Moon.
Thither all those who had opposed the establishment of the World Federation, together with all persons convicted for the fourth time of a felony, had been transported, to superintend the efforts of these dumb, unhuman Moon dwellers. For it had been discovered that the Moon craters were extraordinarily rich in gold, and gold was still the medium of exchange on Earth.
To supplement the vestigial atmosphere, huge stations had been set up, which extracted the oxygen from the subterranean waters five miles below the Moon's crust, and recombined it with the nitrogen with which the surface layer was impregnated, thus creating an atmosphere which was pumped to the workers.
Then a curious discovery had been made. It was impossible for human beings to exist without the addition
