A sudden burst of light, stronger than the meridian sun, flashed into Epworth’s face, causing him to jump excitedly.

“Holy smoke!” he exclaimed. “Is the ship on fire?”

“The general is throwing open all the windows,” Michael Strauss replied from outside of the door. “We are approaching the moon. Come out and peep through a windowpane. It is safe. The crew is busy at the far end.”

Epworth slipped out of Joan’s cabin into the companionway. From where Michael stood they could see out and downward. Far below him Epworth saw a rounding world, full of deep pits, enormous craters, steep mountains. For several moments he gazed at it in silence and awe, and then his mind flashed back to a previous air ride he had taken. This was almost exactly like flying over Mount Vesuvius.

He was still standing at the window gazing downward when Joan and Billy joined him.

“That prisoner in there,” Billy observed. “What are we going to do with him if we make a landing? From what I see we are about ready to drop.”

They shot suddenly across a range of high mountains and came to a long level stretch of shimmering white.

“If a landing is made we will have to tie him up and——”

Epworth had not completed his sentence when the Aerolite dropped downward and landed as light as a feather. When he turned to look out again he discovered that they were located on the peak of a high mountain that sheered off almost straight down for ten thousand feet to a long level stretch of land composed of brownish colored soil. This stretch of land sloped gradually eastward. Remembering that east was west and west was east on the moon, Epworth tried to establish the point of landing from his knowledge of the surface of the moon as outlined by Flammarion. The moon, he knew, was now full, and the entire surface was flashed with sunlight—that is the portion that faced the earth.

But, to his astonishment, they were not landing in the light of the sun.

When the ship came to a stop and he was able to get a better view of their surroundings he discovered that they were surrounded by a dim reflected light that came from the east. On the west the darkness was steadily deepening. While he was still watching the darkness in wonder, the colonists began to pour out of the ship onto the moon.

They looked strange—not at all like men—and Epworth gasped slightly as he recognized the fact that they were encased in air helmets, and wore heavy iron shoes to maintain a balance on the light gravity of the small globe.

The moment they landed the men began to unload sheets of metal silvered into giant reflectors.

“W-w-what are they going to do?” Joan gasped in astonishment. “Why all those sheets of silvered metal?”

“That Toplinsky is a deep man,” Michael responded in awe. “He has never been on the moon before, but he has a great scheme to make it inhabitable by men. That silvered metal, when completed, and erected, will be his first moon mirror. If you notice it is to be erected on a particular point of this mountain—just beyond the part visible from the earth. For fourteen days the sun will be reflected directly toward the earth, and then the rays will move further westward, finally presenting only a dark sphere to the earth. This results, Toplinsky says, in the establishment of a line on the moon which is always lighted by the appearance of the sun in the distance. This line travels into the sunlight and retains the light of the sun while the face of the moon fronting the earth is dark. Thus, at a point only several miles removed, when the sun disappears from the Sea of Vapours, we will say, it touches the mountain system on the west and remains there until the moon’s movements shift it back again. Toplinsky’s scheme is simple. He intends to locate mirrors on that line, catch the light of the sun as it disappears from the part facing the earth, and reflect its heat down into the valley. With the heat naturally will come the reflected light. In this manner he will build solar heaters to overcome the cold and darkness of the long night. Naturally he will locate his colony close to the mountain where it will be near the solar heaters.”

Hardly had Michael finished his explanation when some of the colonists re-entered the airship, and started the machinery. Again they lifted in the air. But they were not up long. For ten minutes they sailed over a dark line where the rocks showed beneath them rugged and mountainous, and then they flitted like a long silent streak across the line of darkness into a brilliant sunlight. Here Toplinsky dropped the airship quickly to the ground, and presently they landed in a small, narrow valley on the bank of a lake half a mile in diameter.

“That is some more of Toplinsky’s work,” Michael explained. “He made that lake by shooting rockets filled with water from the Arctic Ocean. The rockets also contained liquid air and enough hydrogen and oxygen to protect the water from evaporation.”

Epworth sauntered down the companionway, and peeped out of the door. The colonists were again leaving the ship, protected by their air helmets.

“Does he expect to find hydrogen, oxygen, nitrogen, and other elements here?” Joan asked.

“He left orders for the men behind to continue to shoot the rockets filled with chemicals at a certain spot, gradually drawing eastward so as to enlarge the lake.”

“It is light enough here,” Epworth observed, “but I perceive that Toplinsky has landed in a spot where the country is shaded for ten miles by the high mountain on which he left his mirrors. That mountain must be six miles high.”

“Another part of his colonizing scheme,” Michael explained. “He thinks that if men can be protected from the rays of the sun the heat will not be unbearable during the long day.”

“I see.” Epworth was considerably astonished at the giant’s scientific ideas. “The shadow of the mountain will certainly moderate the heat, but I am yet to be convinced that he can generate enough heat with his mirrors and solar heaters to warm up the valley during the long night.”

“Leave it to him. See that long strip of light?”

Michael pointed to a narrow slit of sunlight that suddenly shot down from the top of the mountain. It came straight down like a ladder, piercing the darkness of its source and dropping down in brilliant coruscations on the rugged rocks on the west end of the little lake, and sweeping swiftly over the level stretch of land between the mountain and the lake. It brought brilliant light and heat.

“I’m for getting out of here,” Billy put in.

“Fine,” Epworth replied scathingly, “but how are you going to live out there? The colonists are wearing air helmets, and that indicates to us that if we undertake to leave the Aerolite we must find some way to store oxygen over our own heads.”

“There are air helmets in the storeroom,” Michael suggested, “and an oxygen tank in the cook room. Perhaps——”

But without waiting for a command from Epworth, he sped down the companionway into the kitchen. When he came back he was carrying three air helmets.

“Here you are,” he said energetically. “I found them hanging near the kitchen oxygen tank, and of course filled them so that you can use them.”

“But, how will we refill them after we exhaust the supply now imprisoned in them?” Epworth protested. “I——”

“I brought along a recharger, and——”

“Even so, one recharge will not last us long.”

“Perhaps we may not need them after all,” Joan suggested. “The colonists are taking them off their heads.”

Epworth opened the window cautiously and stuck his head out.

“There is atmosphere here,” he observed slowly, “but it is exceedingly thin.”

“It is not half as thin as these air helmets promise to become,” Billy snorted, “and I think I can explain it. The astronomers on the earth cannot see deep into these craters. They see only the tops of the mountains, and the atmosphere has done the same as it does on the earth—sought the lower levels, being pressed down from above and gathering density in the holes and caves.”

“That being the case right here we separate from Toplinsky,” Epworth decided quickly. “If we wait he will put a watch over the ship, and cut off our escape.”

“You say that Toplinsky has been shooting liquid air, oxygen, nitrogen and hydrogen up here?”

Joan put the question to Michael as if she had just heard this, and Epworth looked at her in surprise.

“Of course,” Epworth answered, taking the words out of Michael’s mouth. “That has been gone over half a dozen times.”

“True, but a new idea has just struck me. Perhaps the liquid air and all the other ingredients that make air, which Toplinsky shot up here, made good breathing air when the explosions occurred and that enough have been unloaded from the earth to create a small air circle at this point.”

“Such atmosphere would be held down at this point by the pressure from above,” Epworth agreed, “and remain in natural form.”

“If my theory proves true,” Joan continued, “we can breathe only when we are near the lake.”

“Be that as it may, we will go out and see how we get along but be sure to hold on to your air helmets.”

Locking the prisoner inside of the small cabin the three Americans moved softly down the companionway toward the kitchen. On the way they caught a glimpse of Toplinsky and his men standing in a circle, with their air helmets in their hands, while several of the company were turning up the soil with shovels for Toplinsky to examine. The scientist was doing this carefully, and Epworth could not restrain a thought of admiration. The man was certainly a thorough scientist, and in his scheme to make the moon inhabitable he would be sure to plant vegetation that would grow prolifically.

Michael had informed them that there was a companionway beyond the kitchen which would lead them to the opposite side of the ship, and they had been thoughtful enough to get instructions that would enable them to locate it. When they arrived at the kitchen they found it deserted, the entire outfit having rushed to see the landing, and with very little trouble they gained the companionway. But when they came to the door that opened out on the small balcony on the opposite side they found it locked.

For several moments the two men were puzzled. Epworth fumbled at the lock without result, and then Billy took his place. Billy, being a mechanic of great ability, used the blade of his knife and after working for some time forced the bolt back, and pulled the door inward. With beating hearts they ran down the ladder and stepped upon terra firma.

Here they paused for a brief consultation. They were hidden from Toplinsky’s men by the airship but it was evident that if they escaped they would have to run for it in the open. The nearest protection consisted of a range of small mountains on the south. There were other mountains on the north but these were too far away, although they were taller and more promising as a hiding place. Both ranges appeared rocky and rugged, treeless and desolate. In front of the Aerolite, stretching as far as the eye could reach was a pitted desert of white ashy sand dunes; behind the machine was the newly made lake which rippled softly on a nearby beach; beyond this the mountain with the solar heat.

“We will have to try the southern mountains,” Epworth said briefly, “and run like scared rabbits. It is lucky, Joan, that you are wearing short skirts.”

“Let us scatter,” Billy proposed, “and meet at that large rock which is projecting over that lower mountain.”

“Not me,” Joan objected quickly. “I’m staying close to Julian. I might need his strong right arm.”

“Then all together.”

They kept the Aerolite between them and their enemies as long as possible, and then broke into a run.

Their attempt to run was at first ludicrous. Being used to the gravity drag of the earth they put forward all their efforts in taking long quick steps. Instead of steps these muscular movements proved to be jumps, and they moved like Jack in the Magic Boots, covering about thirty yards in a single step, and jerking their legs up ludicrously when they took the next step. In fact, after getting off the ground it took an effort to put their feet back.

Joan immediately tumbled over, laughing somewhat fearfully.

“This will not do,” she exclaimed anxiously, as she fell the second time. “I can’t run. Let us walk.”

Epworth, the second step he took, discovered the situation, and was moving in accordance with what he thought a moon action should be. It was not perfect but it kept him from falling and was a rapid mode of advance. He now stopped and gave them instructions in the way he thought they should move. While he was doing this Toplinsky came around the side of the Aerolite and discovered them. At the time they were probably about twelve hundred feet distant.

“Ah, ha, they run,” he shrilled in that sharp voice they had learned to dread. “Our guests are wearying of their entertainment. They would leave us without bidding us farewell. Atta, boys, up and after them!”

He started on a big run for the Americans. Epworth expected to see him fly up and turn over but the giant was too scientific-wise. He came on with a hop-skip-and-jump that seemed to make him fairly skim over the ground.

“A regular flying squirrel,” Billy grunted, “and dangerous as a snake.”

Toplinsky landed in front of Epworth with a broad grin.

“Ah, ha, ho, ho, my bantam American pugilist, we meet again, and on different footing. This time we shall fight in the same way, but with different results. Then I shall be freed of my promise.”

He stared savagely for several seconds into the American’s face, and then leaning forward, with his little eyes twinkling, he aimed an ugly blow at Epworth’s head. The American attempted to dodge it but the difference in the gravity pull made him clumsy and he half-floated to one side, the blow striking him on the chest, spinning him around and rolling him forty feet.

“Run, Joan,” he shouted. “Make for the mountains. I can’t fight here. Billy will take care of you while I hold this great brute.”

He scrambled to his feet as Toplinsky tore down on him.

“Shall I shoot him?” Billy asked softly.

“And stay on the moon all the rest of your life?” Toplinsky shrilled. “Shoot, will you? Shoot! I’m the only man who can take this expedition back to the earth.”

He stopped, tore open his shirt and exposed his hairy chest.

“Run,” Epworth urged. “Keep your cartridges as long as possible. I will attend to this gentleman.”

Without waiting to see what Billy did, Epworth squatted, sprang forward, and threw his arms around Toplinsky’s legs, jerking at them with all his strength. The result was exceedingly funny.

Toplinsky threw out both hands, waved them wildly, and attempted to fasten himself down with his powerful leg muscles. But this time light gravity aided the American, and he was able to shove the giant’s feet from under him. For a second Toplinsky was a bundle of flying arms and legs threshing the air and he fell in half a dozen directions. Joan, looking back, laughed outright.

To be laughed at was the crudest punishment that could be inflicted on the egotistical scientist. He let out a bellow like a bull, and made a desperate, thoughtless effort to stand up. The effort proved a contortion of muscles in the wrong way, and he sprawled in every direction again.

There was now no mercy in Epworth’s battles with this man, and he was not overlooking an opportunity. The first assault by the giant had taught him caution, and now he moved slowly, thoughtfully. He was not a man to draw a weapon carelessly on a man but he was fighting for the lives of three people. He could not afford to be squeamish. This was not like fighting on the earth. He was physically outclassed.

Drawing his gun he brought the butt down on Toplinsky’s head with all the force he had in his arm.

The giant was like an ox but the blow knocked him out.

By this time Toplinsky’s men were stumbling over each other to get to the fight, and pausing only for a second to get the direction in which Joan and Billy had gone, Epworth adopted Toplinsky’s method of travel, and departed with a hop-skip-and-jump. The progress he made was startling, and very soon he was some distance away from the pirate band, and had caught up with his companions.

“Do this,” he instructed. “Make it snappy. The giant will be after us shortly.”

But again Toplinsky proved wise. When he discovered that his companions could not master the art of advance, he did not give chase. He knew now that Epworth had a gun, and he was not anxious to push a contest where the gun would have to be used. Thus the three fugitives reached the mountains, and found refuge in a cave, the entrance of which they blocked with a large boulder.

“We’re sitting pretty now,” Billy remarked as he rolled a cigarette, “but I am wondering what we are going to eat and drink?”

The three Americans looked gravely out at the dreary waste land. Not a sprig of green grass, not a tree, not a sign of a spring—only barren white sand dunes, climbing cliffs with crater-like holes in them, and the food and water supply in the hands of men who would kill.