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 of 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.
he 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.