those elements existing in the air in minute quantities – neon, krypton, and argon. And the ships that brought the gold bars back from the Moon had conveyed these gaseous elements there.
The droning of the sixteen atomic motors grew louder, and mingled with the hum of gyroscopes. The ladder was drawn up and the port hole sealed. On the enclosed bridge Nat threw the switch of durobronze that released the non-conducting shutter which gave play to the sixteen great magnets. Swiftly the great ship shot forward into the air. The droning of the motors became a shrill whine, and then, growing too shrill for human ears to follow it, gave place to silence.
Nat set the speed lever to five hundred miles an hour, the utmost that had been found possible in passing through the earth's atmosphere, owing to the resistance, which tended to heat the vessel and damage the delicate atomic engines. As soon as the ether was reached, the speed would be increased to ten or twelve thousand. That meant a twenty-two hour run to the Moon Colony – about the time usually taken.
He pressed a lever, which set bells ringing in all parts of the ship. By means of a complicated mechanism, the air was exhausted from each compartment in turn, and then replaced, and as the bells rang, the men at work trooped out of these compartments consecutively. This had been originated for the purpose of destroying any life dangerous to man that might unwittingly have been imported from the Moon, but on one occasion it had resulted in the discovery of a stowaway.
Then Nat descended the bridge to the upper deck. Here, on a platform, were the two batteries of three ray-guns apiece, mounted on swivels, and firing in any direction on the port and starboard sides respectively. The guns were enclosed in a thin sheath of osmium, through which the lethal rays penetrated unchanged; about them, thick shields of lead protected the gunners.
He talked with Benson for a while. "Don't let Axelson get the jump on you," he said. "Be on the alert every moment." The gunners, keen-looking men, graduates from the Annapolis gunnery school, grinned and nodded. They were proud of their trade and its traditions; Nat felt that the vessel was safe in their hands.
The chief mate appeared at the head of the companion, accompanied by a girl. "Stowaway, Sir," he reported laconically. "She tumbled out of the repair shop annex when we let out the air!"
Nat stared at her in consternation, and the girl stared back at him. She was a very pretty girl, hardly more than twenty-two or three, attired in a businesslike costume consisting of a leather jacket, knickers, and the black spiral puttees that had come into style in the past decade. She came forward unabashed.
"Well, who are you?" snapped Nat.
"Madge Dawes, of the Universal News Syndicate," she answered, laughing.
"The devil!" muttered Nat. "You people think you run the World Federation since you got President Stark elected."
"We certainly do," replied the girl, still laughing.
"Well, you don't run this ship," said Nat. "How would you like a long parachute drop back to Earth?"
"Don't be foolish, my dear man," said Madge. "Don't you know you'll get wrinkles if you scowl like that? Smile! Ah, that's better. Now, honestly, Cap we just had to get the jump on everybody else in interviewing Axelson. It means such a lot to me."
Pouts succeeded smiles. "You're not going to be cross about it, are you?" she pleaded.
"Do you realize the risk you're running, young woman?" Nat demanded. "Are you aware that our chances of ever getting back to Earth are smaller than you ought to have dreamed of taking?"
"Oh, that's all right," the girl responded. "And now that we're friends again, would you mind asking the steward to get me something to eat? I've been cooped up in that room downstairs for fifteen hours, and I'm simply starving."
Nat shrugged his shoulders hopelessly. He turned to the chief mate. "Take Miss Dawes down to the saloon and see that Wang Ling supplies her with a good meal," he ordered. "And put her in the Admiral's cabin. That good enough for you?" he asked satirically.
"Oh that'll be fine," answered the girl enthusiastically. "And I shall rely on you to keep me posted about everything that's going on. And a little later I'm going to take X-ray photographs of you and all these men." She smiled at the grinning gunners. "That's the new fad, you know, and we're going to offer prizes for the best developed skeletons in the American Province, and pick a King and Queen of Beauty!"
"A radio, Sir!"
Nat, who had snatched a brief interval of sleep, started up as the man on duty handed him the message. The vessel had been constantly in communication with Earth during her voyage, now nearing completion, but the dreaded A-A-A that prefaced this message told Nat that it came from Axelson.
"Congratulations on your attempt," the message ran, "I have watched your career with the greatest interest, Lee, through the medium of such scraps of information as I have been able to pick up on the Moon. When you are my guest to-morrow I shall hope to be able to offer you a high post in the new World Government that I am planning to establish. I need good men. Fraternally, the Black Caesar."
Nat whirled about. Madge Dawes was standing behind him, trying to read the message over his shoulder.
"Spying, eh?" said Nat bitterly.
"My dear man, isn't that my business?"
"Well, read this, then," said Nat, handing her the message. "You're likely to repent this crazy trick of yours before we get much farther."
And he pointed to the cosmic-ray skiagraph of the Moon on the curved glass dome overhead. They were approaching the satellite rapidly. It filled the whole dome, the craters great black hollows, the mountains standing out clearly. Beneath the dome were the radium apparatus that emitted the rays by which the satellite was photographed cinematographically, and the gyroscope steering apparatus by which the ship's course was directed.
Suddenly a buzzer sounded a warning. Nat sprang to the tube.
"Gravitational interference X40, gyroscopic aberrancy one minute 29," he called. "Discharge static electricity from hull. Mr. Benson, stand by."
"What does that mean?" asked Madge.
"It means I shall be obliged if you'll abstain from speaking to the man at the controls," snapped Nat.
"And what's that?" cried Madge in a shriller voice, pointing upward.
A cross the patterned surface of the Moon, shown on the skiagraph, a black, cigar-shaped form was passing. It looked like one of the old-fashioned dirigibles, and the speed with which it moved was evident from the fact that it was perceptibly traversing the Moon's surface. Perhaps it was travelling at the rate of fifty thousand miles an hour.
Brent, the chief officer, burst up the companion. His face was livid.
"Black ship approaching us from the Moon, Sir," he stammered. "Benson's training his guns, but it must be twenty thousands miles away."
"Yes, even our ray-guns won't shoot that distance," answered Nat. "Tell Benson to keep his guns trained as well as he can, and open fire at five hundred."
Brent disappeared. Madge and Nat were alone on the bridge. Nat was shouting incomprehensible orders down the tube. He stopped and looked up. The shadow of the approaching ship had crossed the Moon's disk and disappeared.
"Well,
