The Drowned Planet

Professor Appleton, the famous scientist who journeyed through space from the Earth to Mars in his wonderful Marsobus, accompanied by

Teddy Craig, a schoolboy, Mackenzie, a Scottish engineer, and Ashby, a hardened globetrotter, in making the attempted return to Earth finds that a mysterious planet, which has puzzled him from his observations from Mars, is in his trajectory, and he determines to explore this strange body. The planet, he finds is a kind of water world where giant fish disport themselves in the depths and queer people with shining fish-like garb cruise in vessels of great size. Ashby, horrified by the appearance of the denizens of the deep, has a nervous breakdown and has to be tied down, but the remainder of the part, anxious to investigate, are captured by the people of the boats, their downfall being brought about by the means of great nets.

Chapter 1. The People of the Water World
Chapter 2. Ashby's Last Hope
Chapter 3. Ashby Works Alone
Chapter 4. Adrift on the Ocean
Chapter 5. Beneath the Barrier of Ice
Chapter 6. In the Grip of the Torrent
Chapter 7. Appleton in the Hands of the "Gill-Men"
Chapter 8. War in the Great Cavern
Chapter 9. Secrets of the "Gill-Folks'" City
Chapter 10. Where Is the Marsobus?
Chapter 11. A Madman's Treachery
Chapter 12. The End of the Troglodytes
Chapter 13. The Great Catastrophe
Chapter 14. Homeward-Bound!

LIST OF ILLUSTRATIONS

Illustration 1. In front of him was the terror!...
Illustration 2. One of the men was gesticulating and speaking to Appleton...
Illustration 3. On one side of the waterway a stalagmite had been formed into the shape of a hideous monster.
Illustration 4. The great arm of the idol fell; in place of the slowly moving river there was a raging torrent.
Illustration 5. Appleton it was who fired the first shot.
Illustration 6. "Fall to," Appleton ordered, and the four of them began to hew away at the rock.
Illustration 7. The overhanging crowns of the icebergs seemed as though they were about to tumble in thunderous weight.

CHAPTER 1
The People of the Water World

PROFESSOR APPLETON, the man who had made the tremendous journey from Earth to Mars and was now on the way back, with Teddy Craig, Mackenzie the engineer, and Ashby the globe-trotter, in the wonderful machine called the Marsobus, looked through the windows of the craft, filled with various emotions, at the strange new world to which the Marsobus had come.

There was sufficient to give the adventurers cause for thought—serious thought. They had seen from afar off the wonder of a world that seemed to be nearly all water—a phenomenon for which Appleton, most famous of scientists, had been prepared as the result of his observation of the celestial body. True, they did not know what lay beyond the limits that they could see, any more than a man flying over mid-Atlantic would know that it was bordered by solid earth. But there was this difference, at any rate: Appleton's theory was that, with an atmosphere as dense as he had found that of this strange world to be, there was certainly a very disproportionate amount of water as compared with land-masses.

It was this phenomenon that had intrigued him to descend upon the planet, not with the intention of remaining there for any length of time, but in order to make some investigations regarding what had been a mystery to him ever since the time when, viewing the vast expanse of space from Mars, he had found some intervening body between Mars and the Earth—some body that not only cut off the sight of the tiny gleam that represented the Earth, but also interrupted the wireless communication that had been possible previously.

"Fellows," he said, after watching for a while the figures on the fairly large island, now growing more distinct, and the great ships that were lying off, "I think, after all, it would be best if we alighted on the water, and tried to get into touch with someone on one of the ships."

"Something spectacular may help us," Craig told him. "We don't know what sort of people these are; and if we made a dive into the water and disappeared, only to come up to the surface again a little later, they might be impressed. What do you think?"

"A good idea, indeed!" Appleton agreed. And a swift manipulation of levers changed the direction of the Marsobus so that she dived for one of the many ships which were moving through the water, or lying in what was evidently a harbour. Most of these vessels were huge affairs, greater than any that the adventurers had ever seen. They possessed no funnels or masts. They were tall-sided and of great width, bow and stern being similar in construction, and the appearance of the Marsobus on the water was the signal for several of them to rush forward as if to ram her. Appleton was quick to act; he set the levers of the machine so that she rose vertically, escaping a collision only by the merest shade. Looking down upon the top of one of the ships thus robbed of their victims, the occupants of the Marsobus saw that it was crowded with moving figures, all staring up at the strange visitant, undoubtedly, as the binoculars allowed to be seen, in no small trepidation.

By a touch of his lever he made the Marsobus dive, seemingly for the particular ship they were over; and there was a rush on the part of the figures which disappeared and left the deck clear.

"I don't think we've got much to fear, fellows," Appleton said. "We'll go down again now and submerge, and see what the effect is. Strange, isn't it—there seem to be no buildings on the land, except those down by the shore? It looks as though these people are water dwellers."

Suddenly he let the Marsobus descend vertically; she alighted on the water, well away from any ship, and before any one of them could attempt to attack her the submersing apparatus caused her to begin to sink beneath the surface—while Ashby and Craig, standing at the uncovered but watertight window, saw the astonishment of the people on the deck of the ships.

"Light on, Chief," called out Mackenzie, and Appleton switched on the light. The "splash" of it in the water, as the Marsobus sank still lower, produced a weird effect, and scores of strange-looking fish went scurrying away before the unwonted vision presented to them; and some of the creatures were huge things, octopus-like, but larger than any octopus of which Appleton had ever heard.

Their appearance was sufficient to inspire something like astonishment into Teddy Craig at least, while Ashby gave vent to exclamations of terror.

"Heaven knows what they are!" he cried, trembling all over. "For mercy's sake, Chief, get away! It's horrible! I can't stand it!"

It was a revival of the nervousness that had overcome Ashby when Appleton had first suggested stopping on the water planet, and Appleton was afraid for him.

"It's all right, old chap!" he called out. "Those—those things are more scared of us than we need be of them. They can't hurt us in here! Look at 'em!"

There was no need for that injunction as far as Craig and Mackenzie were concerned, for they were watching intently the octopi scurrying away.

"Other weird creatures there were too, with long gleaming bodies as of fishes, with tails behind them, with fins that seemed to be out of proportion to their size, and, most striking of all, with heads which, following to the line of the body without plainly marked necks, were very animal-like in appearance except for the fact that, the ears were gill-like, and worked in keeping with the movements of the mouth that was set below a slightly protruding nose. The four fins of these strange creatures were like those of sea-lions, and the eyes set on each aide of the head were slit-shaped and covered with constantly moving lids. In fact, the combination suggested the sea-lion.

"Rummy's the word," Mackenzie agreed. "Sort of nightmare a fellow might have after too many rations of rum. Here, Ashby, old chap, pull yourself together!"

The man was still trembling and ashen-faced, and it was clear that he was on the verge of a nervous breakdown. Appleton, alarmed, realized that it would be a mistake to prolong the ordeal unnecessarily, and touching the button that controlled the movable shutters, he so cut off the scene, except from the steering cabin where he himself was seated.

As he thus ruminated he was working the Marsobus forward and not downward, so that it came to a sudden stop—with a crash and a grating which all knew meant that she had fouled some sunken rock.

Immediately Appleton ascended to the surface, intent on seeing if any damage had been done—a quite unlikely contingency because of the peculiar metal of which the Marsobus was made. He unslid the window-shutters, and the little party, peering across the water, saw that they were within a few hundred yards of the shore of the island that they had viewed from above.

They saw, too, that there were large numbers of the strange fish-like creatures swimming towards the land, on which were a crowd of people.

"What are we going to do, Chief?" Mackenzie asked. "Shove out the collapsible boat and—"

"I'm not going—I'm not going!" almost screamed Ashby, making a threatening rush at Appleton. There was a mad light in his eyes, and Mackenzie, fearing what he might do, grabbed hold of him. The next instant the pair were struggling fiercely on the floor of the central cabin, and Ashby, strong with the added strength of madness, fought ruthlessly. Mackenzie, however, was no weakling, and realizing that in his madness Ashby would have no mercy, the Scotsman exerted every effort to conquer him.

"Keep off!" Mackenzie gasped, as lying on his back, with Ashby over him, he saw Appleton approaching.

Next moment, with a sudden movement, Mackenzie had brought his knees up with a great force and struck Ashby in the body.

The frenzied man went flying across the saloon and crashed against a chest, falling to the floor and lying stunned.

"Poor beggar!" said Appleton again. "We shall have to do something for him. Let's put him in his bunk."

It took all of five minutes to get the unconscious man into his bunk, where he lay like a log.

"We don't know what's going to happen next," Appleton said. "And I think it would be wise to take precautions with him. I hate to do it—but I suggest we bind his wrists and ankles."

"I think you're right, Chief," Mackenzie agreed. And this, to them, very distasteful task was carried out.

"Now, we'll see what's happened to the bus!" the Professor exclaimed, and the trio gazed through the window.

Appleton turned the Marsobus about and drove her towards one of the great ships.

"They're as scared as mice, Chief!" Teddy Craig said excitedly. He had been looking through the window and had seen the hurried movements of the strange vessels that looked like floating houses the nearer they were approached. There was, however, no attempt this time to drive off the Marsobus, no movement to attack her, for which, naturally, the adventurers were not a little pleased.

"It's going to make our chances better and things much easier for us if they're afraid," Appleton said, as, with her remarkably constructed floats that automatically issued from the Marsobus when necessary, the machine rode on the water, and the Professor opened the door that gave exit. "We'll see what we can do to get into touch with someone."

The rope ladder was thrown out, and Appleton himself went out and stood on it and waved his arm towards the nearest of the ships. It was one of the largest, and, being only about thirty yards away, towered above the long tapering body of the Marsobus.

Appleton needed not to shout to attract attention, because the side of the ship, in which were a large number of port-holes, showed faces of people looking at the Marsobus. Strange faces they were, too. Bullet shaped, with large round eyes deeply set, and overhung by pendulous lids; a mouth that showed thick and red-lipped through a mass of hair, beneath which Appleton surmised ears must also lie hidden, since they were not to be seen. Such was the appearance of these folk who stared at what they must have considered to be the equally astonishing figures on the Marsobus.

They were curious, they were excited, and they were afraid these three facts were clear enough to Appleton who, for a moment or two, did not know what to do; he was afraid lest if he went over in the collapsible boat it would be the signal for hostile action to begin.

"We've got to take the risk, though," he said over his shoulder to Mackenzie and Craig, who were looking out of the top of the Marsobus. "Bring up the boat!"

It was done, and Appleton suggested that he and Craig should go over while Mackenzie remained behind, ready, if necessary, to take action with one of the guns.

"I'll punch a hole right through that ship, mon," he said, "if they try any monkey tricks. They look now as though they might too!"

The appearance of the boat on the water, with Craig and Appleton in it, had changed the attitude of the people on the ship; they had rushed from the port-holes, which were covered now, and had gone on to the top deck, standing there in a dense mass and armed with long spears, each of these having two barbed points to them. For the first time the adventurers had their view of the full length of the people. Almost ape-like as they were about the head, their bodies were very different from those of apes. Indeed, they looked for all the world like fishes. They were arrayed in shining raiment that gave them the appearance of being clad in chain-mail. Appleton, however, quickly saw that this was not the case, that the clothing was, apparently, made from the skins of fishes. The effect was remarkable enough, indeed, for these people looked half men, half fish.

They carried, all of them, long sticks pointed at the end, each with two barbs; and these they were waving threateningly towards the Marsobus.

"They look like knights in armour!" Teddy Craig exclaimed. "Sort of King Arthur crowd! I lay, Chief, let's go ashore!"

"Right oh!" Appleton agreed. And a few moments later the rope ladder was let down, and the collapsible boat was launched. Into it the adventurers dropped, each armed with his automatic.

Appleton, sitting in the stern, saw the commotion that was caused amongst the crowd on the shore; they were evidently not at all pleased at the movements of these strangers, and suddenly after a brief and seemingly heated discussion they took action.

Scores of them raised their barbed spears and hurled them at the approaching boat, then no more than thirty yards away. Fortunately Appleton read the signs aright, and cried, as he slumped to the bottom of the boat:

Craig obeyed, leaving the oars hanging in the rowlocks. Spears went hurtling over the frail craft, to fall into the water harmlessly. Several of them, however, found resting-places in the shell of the boat, and the holes that the barbs tore let in the water so rapidly that the vessel began to sink. At the same instant, although neither of the crouching pair saw it, the great ships were moving towards the Marsobus.

"We've got to go overboard, Teddy," Appleton said, as he saw the water rushing in. "Now!"

Together they went over and began to strike out for the Marsobus, where, as they saw, Mackenzie was standing at the gun, which was run out through the port-hole. Glancing behind him Appleton saw the reason for the engineer's action. He realized that Mackenzie was going to try to hold off the ships while he and Craig reached the safety of the Marsobus.

One shot only did Mackenzie fire at the ships behind the swimmers, and then, springing from the gun, he was at the door on top of the Marsobus, firing rapidly with his automatic.

The last word was sufficient to make the swimmers look hurriedly over their shoulders, and they saw indeed a grim monster slicing through the water after them, its vicious-looking "sword" flashing as it came. It was fewer than twenty yards away, and at the rate it was moving Mackenzie felt that there was little hope for his comrades unless he were lucky enough to get home a shot. It was no easy matter, especially as the Marsobus was rocking to the motion of the water, and as the people on the nearest ship were hurling more spears, thinking, no doubt, that they had their chance presented to them while the strange-looking individual on the queer vessel was so busily engaged in trying to save his companions' lives.

Nevertheless Mackenzie, not deigning to seek cover, continued to fire until his pistol was empty, almost moaning as he each time missed.

Appleton and Craig were swimming as they had not swum before, slicing through the water straight for the Marsobus, caring nothing for the spears that plonked into the water around them, their one anxiety being to escape the terror behind them.

Neck and neck they raced, urged on by Mackenzie, who in his frenzy to help was now swinging by the rope ladder.

"Come on!" he cried out, as Craig came within a few feet—Appleton, with fine courage, having eased up a little to enable the younger man to get to the ladder first. One final spurt, and Mackenzie had Teddy by the hand.

"Can—manage!" Craig gasped, realizing that after all it would be easier to act on his own, and Mackenzie let him alone.

Teddy grabbed the ladder and hauled himself up, and a moment later there came an agony-filled cry from Mackenzie. Teddy told him that Appleton had been caught, but he felt the ladder beneath him shake, glanced over his shoulder, and saw Appleton scrambling up the ladder, having reached it just in time to avoid the flashing sword of the monster.

There was no need for him to finish the sentence. The three men dropped into the Marsobus, hauled in the ladder, shut the door just as a shower of spears came over, clinking on the shell of the machine.

Through the window they saw the swordfish dashing itself against the side of the Marsobus, but they knew that that could do no harm. Nevertheless, Mackenzie, angry at having missed it so badly before and having reloaded by now, fired again through the gun-port and succeeded in getting a couple of shots in the fish's body. The water was dyed red, the sword-fish lashed about furiously, then made one more dash, but never finished it. It died in the midst of its rush.

Now that the episode was over, the three men were trembling like children, and it was some time before they could gather themselves together. It was Appleton who recovered clear-headedness first, and he pointed a still shaking hand at the ship that was nearest the Marsobus.

"I did, mon!" Mackenzie agreed, with a slight laugh. "I told you that I'd punch a hole clean through any that tried tricks. It stopped 'em coming, too. The moment that shell plonked in the whole bunch of them hove to, though they did throw in some more spears. But what are they doing now?"

This was signalized by considerable excitement being displayed by the people whom the adventurers could see at the port-holes of the ships. It was as though they were shouting their pleasure at having seen the creature killed, and Appleton said to Mackenzie: "Seems to me they're rather bucked about that shot of yours—I mean the one that killed the sword-fish. I vote we take advantage of that; it may make things a bit easier for us."

"Well, we'll make another attempt when Teddy and I who look pretty dreadful figures, have changed. I'm chilled to the bone! Keep an eye on things while we change."

"Right oh, Chief!" Mackenzie said. And for the next half-hour he stood by the window looking at the vessels, which made no move to attack nor showed signs of going away. It was as though they were waiting for their strange visitants to make the next move; in fact, a few minutes before Appleton was ready there appeared on the deck of the ship that had been struck by the shell a man who waved his arms as if beckoning, though it was evident, that he was not altogether at ease. He had deliberately thrown aside the spear that he had been holding, and Appleton accepted that as a token of peace.

"We can't afford to risk our only other boat," Appleton said. "I suggest that we drive the bus towards the ship that man is on."

Mackenzie nodded, and went to set the engine working. Appleton steered the Marsobus slowly in the direction of the vessel, and the people who had been at the port-holes promptly disappeared. But the man on the deck, who had given what had been interpreted as an invitation, stood his place, even when the Marsobus came to rest alongside.

"Now, then, up we go—and keep your wits about you," Appleton said. "Pistols all right? Good! Keep 'em in evidence—they may be useful. Come on!"

Up on to the top of the Marsobus the three men went, and found the deck of the ship filled with men. The Marsobus lay many feet below the ship, and the top of it was on a level with the lowest row of port-holes. It was quite easy to see in; but, beyond a casual glance, none of the adventurers wasted time upon that. They were anxious to get to close quarters with the strangers who were leaning over the side of the vessel, gesticulating wildly and jabbering away in a tongue which, while naturally unintelligible, was clearly very simple—as far as Appleton could judge, and he was an adept at philology. They seemed to be getting more excited.

The man who had given the invitation to the adventurers was leaning over and indicating a fixed ladder on the side of the ship, and Appleton, greatly daring, said to his comrades:

"That's an invitation to us to go aboard. We'll do it. Keep your pistols in your hands, and let fly if there's the least sign of trouble!"

He climbed up the ladder, and the others followed him at once. As they reached the top the crowd drew back, and Appleton stepped on to the deck. Craig was immediately behind him, and Mackenzie came over the side just in time to see the rush that took place, and to be taken quite as much by surprise as the others had been.

Scores of the little men leapt forward and made for Appleton and Craig, while others jumped between the ship's side and Mackenzie, who found himself caught in the toils of a net that enveloped him and held him tighter the more he struggled.

Through the mesh of it he saw that an exactly similar thing had happened to his companions who by now were on the deck, struggling wildly, tearing at the nets. The suddenness of the attack had been complete, and the nets, thrown skilfully, not only enwrapped the unfortunate men, but rendered the use of their revolvers impossible. The situation looked desperate.

Craig lost his: knocked from his hand by the net. Appleton, although he still retained his, had no more chance than Mackenzie of using it, because one of the assailants sprawled upon his arm. Evidently the strangers realized that while their "captives" held these weapons they would he dangerous, and were bent on getting possession of them.

And Appleton's they got, after a while, that is. They succeeded in knocking it out of his hand, and it got mixed up in the folds of the net; thereby preventing a danger, not only to themselves, but also, as the Professor knew, to the enmeshed men.

And the thing that Appleton had expected happened. In the struggle that he was still putting up the pistol went off, being noiseless and smokeless. Appleton knew only by the fact that a man who had been trying to subdue him suddenly went backward with an ugly hole in his forehead. At the same time a man, who had been attacking Mackenzie, tumbled to the deck as the Scot managed to fire, and the next moment to have his arm well-nigh twisted off by one of the little men, who, despite their diminutive size, were very powerful.

Wrapped about by the clinging, cloying nets, the adventurers had little chance, and they knew, now that their weapons were gone, they were helpless; and their assailants made pretty short work of them by giving each of them a crack on the head with a flat-bladed weapon like a canoe paddle.

CHAPTER 2
Ashby's Last Hope

AS soon as the adventurers had been reduced to unconsciousness, their assailants set to work to complete the scheme which they had had in mind. The fear that they had displayed was all part of their plot to lure the strangers into their power, as also had been the concealing of arms, except the long barbed spears. They possessed other and more powerful weapons, as their prisoners were to find out before much longer; but they had argued that to appear to have only what were, after all, primitive weapons, would inspire confidence in the visitors, which was just what the inhabitants of the floating houses desired, because they had made up their minds that the ship that could not only fly and travel on the sea, but could also descend into the depths and rise again, was a prize worth obtaining. The desire to possess it unspoilt had been behind their failure to use their more powerful weapons.

The success of their scheme seemed to cause them much pleasure—and it was a very excited body of men who went over the aide of the ship and dropped on to the top of the Marsobus.

There were half a dozen of them, and, after peering curiously into the still open trap of the Marsobus, each man firmly gripping a peculiar-looking object, spherical shaped and having the appearance of a bomb, they climbed into the hole and descended into the main cabin of their prize.

From cabin to cabin they went, touching nothing but gazing curiously at everything. It was as though they were afraid to interfere with things that were strange to them. Certain it was that they were interested very much in the gun which, still protruding from the side, had caused the damage to their own vessel.

They were interested and surprised at all they saw, and held excited conversation about nearly everything.

But their greatest surprise was shown when they found the unconscious Ashby lying in his bunk, where he had been placed after the encounter with Mackenzie. All through the exciting events of the past hour or two Ashby had lain in his coma, and his companions had, when occasion allowed, examined him to make sure that he was still alive. Also, Appleton had several times tried to revive him, but without avail.

The strangers jabbered away when they saw Ashby. They touched the inert body, listened for heart beats, and shook their heads as if to say that the man was dead. Nevertheless, they were evidently not convinced, for while one of them went out of the Marsobus, the others cut the cords that Appleton had placed on Ashby for safety, and when the other man came back they administered something out of a bottle that he had brought, forcing the liquid between the teeth of the unconscious man.

They waited a little while, and then, as nothing happened, forced some more of the medicine into Ashby, holding his head in such a way and rubbing his throat so that the liquid made its way into the body.

But, do what they could, Ashby remained in his coma, and at last, after a short conversation, it was evidently decided that he was dead.

Once again a messenger left the Marsobus, to return after a short while accompanied by another man arrayed in the costume made out of fish skins, but which, instead of ceasing at the waist, continued up to the neck, and with a head-piece made of a sword-fish's head, with the sword as surmounting ornament. The men in the cabin salaamed before him, and then showed him the inert body of Ashby.

With an imperious gesture the new-comer gave an order, and the remaining bonds being slashed. Ashby was lifted up and carried to the top of the Marsobus. By this time twilight had fallen and the face of the waters was covered by a rising mist that hid the not far distant island and shrouded oven the close at hand vessel on which the fight between Appleton and his comrades had taken place. Without any ceremony or delay the bearers threw Ashby into the water. As though inured to death, they stayed not even to see whether their victim sank; the new-comer, evidently a person of high standing, issued further orders, and then clambered up the steps on to his own vessel, followed by all but two of his people—these latter being left on guard in the Marsobus.

Twilight, aided by the ever-increasing mist, deepened rapidly into night, and it was out of the darkness that, a very short time after Ashby had been hurled into the water, a figure climbed like a moving shadow up the side of the Marsobus. As though he were sure of his ground, the climber cared nothing for the rocking of the craft as he made his way to the top, where he paused and peered into the depths of the vessel.

Because of the darkness he could see nothing. Neither could he hear anything. He drew a wet hand across his forehead, as though trying recollect something. It was Ashby.

"Funny," he muttered. "How'd I come to tumble off? And why haven't they missed me?"

And Ashby, whom the sudden immersion in the water had revived, although he came back to life with the loss of memory of everything from the moment when he had made his outburst against being compelled to accompany his friends to the island, dropped, sidled over into the hole in the Marsobus and so made his way down to the dark cabin. He was puzzled by the silence, and told himself that something serious must have happened, because it was certainly unlike Appleton, for one, at any rate, to leave the Marsobus open.

"Perhaps the beggars have gone ashore and got nabbed," he said to himself, as he moved across to the switch and turned on the light, to find himself standing before two weird-looking creatures who, after staring at him for a moment in stupefied silence, burst into shouts of fear and made a rush at him.

Ashby met them. He struck the foremost one full on the point of the chin, and tumbled him back upon his companion. The couple fell in a heap on the floor of the cabin, and next instant Ashby was on them. He was possessed of the strength of madness again, and he pummelled the strangers soundly. One of them he knocked into unconsciousness, and the other, seizing by the throat, he almost throttled before he hurled him across the cabin and crashed him against the side.

"Think that's about put them out," Ashby grunted. "Where the deuce are Appleton and the others?"

That they were not in the Marsobus he quickly saw by going through the machine. He secured an automatic from the arms-chest and went back to the main cabin, to find that one of the men he had knocked out was gone. Ashby rushed up to the top of the Marsobus, and the upglare of light from inside showed him the figure of the man climbing the side of the ship alongside.

Ashby fired promptly, and the man lost his hold, tumbled backward, and dropped into the water.

But if Ashby had hoped that by this he was preventing the alarm being given, he was mistaken; and naturally so, because the light in the Marsobus had attracted attention from several ships, and the one nearest the Marsobus became crowded with men, who showed clearly in the light that seemed to run all round the ship, very much as though there were footlights at the sides of the deck.

Ashby, whose mind seemed amazingly clear after all he had passed through, jumped back into the Marsobus, shut the trap door, set one of the engines working, closed all the ports, and manipulated the submersing apparatus. The Marsobus began to descend, her filtering light through the water being the only sign given of her whereabouts to the people on the ships.

"I've got to find out somehow where the others are," he muttered, glancing across at the man whom he had thrown across the cabin, "The question is how?"

He went over to the man and examined him. Finding that he was not dead, he proceeded to bind the man's wrists, ready against the time when he should recover. He picked up the bomb-like object which was on the floor, where it had been when he first saw the two men after switching on the light.

"Don't like the look of that," Ashby said to himself. "Might be dangerous. Better shove it away."

He took it and laid it in one of the small lockers, and then returned to his prisoner. He tried various means of restoration, and after a considerable time had the satisfaction of seeing the man open his eyes.

"That's better," Ashby said, and then knew himself at an impasse, since the man could not understand him and he could not understand the man, who was staring at him with eyes that held no little fear. It was as though he were seeing a man who had returned from the dead, and Ashby was indeed to him such a man, since he had only a little while before helped to throw him while still unconscious into the water.

Ashby, however, knew nothing of this, and proceeded to make various signs to the man in the hope of being able to make him understand that he was asking where the other occupants of the Marsobus were.

For a long time Ashby continued in this work, but the prisoner maintained an impassive face.

At last Ashby reported to threats. He took the man to the window, through which could be seen the denizens of the deep—creatures that were fearsome enough to scare any man, even as they had scared Ashby himself not so long before; although, strangely enough, they seemed to hold now no horrors for him. Somehow he made the prisoner understand that unless he gave the information that was being asked of him he would be thrown into the water, as it was quite possible to do by means of the diver's outfit that enabled a man to issue from the Marsobus even while it was submerged.

But the man only smiled and shrugged his shoulders. Ashby could not understand it. He put it down to the man's pluck. That this was not so, however—though what else it was he could not for the life of him think, though he was to know later—was proved when he whipped out his pistol and thrust it into the face of the captive. The man instantly began to tremble again, and Ashby, who, of course, had not seen what had happened between Appleton and the people on the ships, at least was able to put two and two together and to guess that there had been trouble, in which pistols had been used to some effect.

"That's got you!" Ashby said; he succeeded, as he thought, in getting the man to agree to take him where the other occupants were.

Ashby, however, was under no delusion regarding the dangers that lay ahead of him, but had little doubt that very determined efforts would be made to take him prisoner as well, and he knew that he would have to work out a plan of campaign.

The first step was to get to the surface, which Ashby was not sorry to do. He switched off the light and set the Marsobus rising close enough to the surface to enable him to use the telescopic periscope. Sitting at the mirror, he examined the reflection and saw the mist-wrapped sea blackened with features that looked like shadows, but which he knew were ships, the indefiniteness broken here and there by splashes of light.

"The beggars are on the look out here," Ashby muttered. "But how the deuce I am to manage things I don't know!"

Not even the fact that he had got the prisoner to agree, as he supposed, to assist him would be much help after all, for the simple reason that it did not seem possible to get to know from him just where the captives were. Ashby pondered over this problem for a long time, and at last decided that it was necessary to interview his prisoner again. He went and fetched him from where he had left him, and, placing him at the mirror, showed him the vague shapes of the ships, his idea being to get him to say if the prisoners were on one of them. How he managed it Ashby never quite realized, but at last he did succeed in eliciting what he took to be agreement that the prisoners were on one of the ships. The question as to which ship was more difficult to answer. Ashby decided to take the risk and to go up to the surface, and, lying well away from the vessel, endeavour to get the man to indicate the one on which the captives were.

Shortening the periscope as he went up, Ashby raised the Marsobus until it was almost on the surface; and then, taking in the periscope altogether, made the machine break surface.

With lights out the Marsobus lay on the water, and Ashby, uncovering one of the windows, peered out, hoping to be able to see the vessels plainly enough for his purpose. As far as he could judge, the Marsobus had ascended to almost the same spot as she had been before, and yet, such was the mist, it was impossible to distinguish the ship near which they had been lying.

Only Ashby had an idea that his comrades were likely enough on that vessel, and at any rate it provided a steering point.

He at last determined to take the chance of turning on the searchlight and sweeping the surface to seek for the ship that had the great hole in its side. Dark as it had been when the man who had escaped him climbed up the near-by ship, Ashby had been able to see the hole, and, putting two and two together, had guessed that it was caused by a shot from the gun of the Marsobus.

The light streamed from the Marsobus and penetrated the mist, breaking upon the ship, which proved to be the one with the hole.

Feverishly Ashby forced his prisoner to look at it, and then shutting off the light made himself understood.

And the prisoner nodded—which Ashby took to mean that his comrades were not on the vessel.

But things were happening. The "enemy" came to life, as it were. From a score of vessels there sprang vivid lights, not in the form of searchlights, but glowing balls as of fire, which threw a brilliance over a very large urea. Followed by these, before Ashby quite realized it, from the crowded decks of the ships that were nearest, there came what to him seemed to be lighted "blankets" thrown with great force. As they swept through, the air, having all the appearance of zigzag lightning, they seemed to spread—and the next that Ashby knew, even as he touched the lever that would have sent the Marsobus back into the depths, was that one of the "blankets" had fallen on the machine. And when he tried to get the Marsobus to move, it was to find that she was held sufficiently to prevent her from making the progress that she ought to have done.

"Caught—like a netted fish!" Ashby rapped, forcing the lever over; but the propeller did not answer, and it came to him at once that it had been fouled. Moreover, the Marsobus was being slowly drawn along the surface, and Ashby's prisoner laughed aloud. Ashby could not see him because of the darkness, and it was perhaps as well for the prisoner, because Ashby was in the frame of mind to have done anything in the moment.

The Marsobus, going along the surface at the will of the unseen power that drew her, was still able to do something for herself; so, at least, Ashby was able to see her as a weapon. There was no need for him to turn on his searchlight in order to pick out an object at which to fire, which was his intention. The lights on the vessels were sufficient to guide him, and, with the enveloping net fogging his vision, he brought out the port gun and, sighting it, fired at the nearest object. That object was a light, which was instantly blotted out, and Ashby knew that he had found his mark.

And then, going to the ammunition cases, he found to his horror that there was but one shell left. At the same time he realized that even had he possessed plenty of ammunition he could not have hoped to do anything more than cause damage to the enemy, who in the end were almost certain to win, seeing that they had managed to catch the Marsobus. Ashby knew that the game was up. It seemed to him that there was nothing for it but to surrender and trust to luck.

Then the thought came to him that after all he ought not to throw in his hand altogether—there were his companions to be thought about. While he remained free there would always be the chance that he might somehow succeed in helping them, though how was a conundrum as dark as the deep blackness of the interior of the Marsobus or the now almost impenetrable gloom outside.

The thought of "outside" seemed to give rise to something in the man's brain. Switching on one of the lights, he moved across the main cabin to one of the lockers in the side, and took from it the diver's headpiece. His captive, who was grinning from behind the heavy beard that shrouded his flat face stared at the strange-looking object. And Ashby, realizing that for the purpose of the mad plan he had conceived, it was advisable that this man should not see what he did, turned off the light again—and there in the darkness he put on the helmet. Then, having seen that his automatic and a fair supply of ammunition were in a waterproof pouch, he moved quietly over to where the emergency under-water exit was. He opened the inner door of it, went inside, fastened it again, and then, touching the push that controlled it—was discarded into the water, the door closing tightly behind him.

It was indeed a wild scheme that he had formed, his object being to get to the inland, which was, after all, only about two hundred yards away not very much of a swim ordinarily, but one that he knew was fraught with danger because of the monstrous fish that seemed to swarm in the waters there. Had Ashby seen that race between his comrades and the sword-fish, not even he might have essayed the foolhardy project on which he had set out; but, as it was, the instant he was in the water he began to strike out towards what he knew was the coast.

"There's one thing," he said to himself as he swam with as little sound as possible, "that prisoner of mine will remain a prisoner, unless his people can smash open the old bus to get at him. And another thing is, with the shutters all closed, they'll think that one of us is inside and yet won't be able to prove it; and, goodness knows, their fellow won't be able to make himself heard through the double shell of the bus."

Ashby also realized that, with the enemy confident that he was in the machine, they would not be on the qui vive for him as they would have been had they known he had managed to get out. The thing that worried him chiefly at the moment was the fact that at any time the enemy might send up more of their brilliant and lasting fire-balls—and it was as a counterfoil to such a contingency that he had donned the diver's helmet, because with it he would be able, if necessary, to swim under water for a very long time, being a splendid swimmer and a stayer.

As luck would have it, however, there was no need for this, as no lights went up. The mist made it dark enough for him to be sure that he would not be seen from any of the ships, while at the same time it made his own work the harder since he had to be careful. He had taken his bearings by the dim points of lights that betokened ships in the mist, and beyond which lay, as he knew, the land for which he was making.

What he would find there, he had not the least idea, neither did he know what he would do afterwards. The present necessity was to get there. So he swam on and on, past the coming wraiths that were ships, and in passing them he swam beneath surface. Constantly there was with him the dread of attack by some monster, and, as every yard was covered, he could have shouted with joy because nothing of the kind had happened.

It was, however, a joy that was short-lived. He passed half a dozen ships, and, seeing the still lights that spoke of the island, had turned aside from his original course, intending to make land at a spot where there was at least no light, whatever else might be there, when suddenly out of the mist there appeared before him two glowing orbs that were not the lights of a ship. They were lights that lived—and moved towards him.

Ashby's heart well-nigh stood still as he saw the great orbs of light which he knew were the eyes; but a second later he was forging away from them, driven onward by the fear that had come over him. He heard a swish and a lashing as of a many-tailed thing, and although he had not been able to see the body he was certain that he was in the presence of an octopus. Gone now was the necessity to keep silent for fear of being heard; in fact there would have been an advantage in having them hear him, since in that darkness Ashby knew that he would be no match for the ogre of the seas if it should come to a fight. Yet he could not shout because of the helmet he was wearing, and his only chance seemed to be to put as great a distance as possible between himself and the octopus. He had whipped his hunting-knife from the sheath where he had placed it before going out of the Marsobus, and he swam with it gripped tightly, even although to do so made swimming difficult. He had turned again so that he was moving towards the lighted shore, willing to take the risk of being seen—and the shore was nearest.

CHAPTER 3
Ashby Works Alone

NOW and again Ashby looked backwards and saw eyes gleaming phosphorescently in the gloom, and thanked providence that he was a good distance away and, as far as he was able to judge, gaining.

Then of a sudden the eyes disappeared; several times Ashby looked round fearfully lest he should see them again, and yet fearfully too, lest he should not. Because somehow he now felt the danger to be greater since he did not know where the brute was. Now he realized that at any moment he might feel the coiling grip of a tentacle about his legs, since the octopus, moving swiftly, silently beneath the water, might be able to gain upon him. Added fear gave added strength, however, and Ashby forced himself forward at a pace that amazed him. And as each yard was covered and yet he was unmolested, he began to think that he would win out after all.

And win out he did, to the extent of getting near to the shore, as he knew by the fact that his feet touched the bottom.

"Thank Heaven!" he breathed, standing up, and he looked out across the water. Behind him now lay the land, with lights that spoke of people and enemies. In front lay—what? The water and—Ashby jumped as, even while he was wondering if the octopus had gone, he felt something touch his foot—something that curled about it.

And then before he had recovered his balance the terror was in front of him. It's shining eyes were there again, and this time he fancied he could see the waving tentacles. At any rate, he felt them the next moment, for they were about him, noisome in their touch and grim in their meaning.

In front of him was the terror! It's shining eyes were
there again, and the tentacles waved menacingly in the air.

Ashby struck out at the dark spot between the eyes, and his knife sank deep, so deep that it was with difficulty that he managed to get it out again. And the tentacles were closing more tightly about him. Again he struck, and well, just at the moment that the darkness was broken by a glare above him, and he knew that once more the enemies from whom he had tried to escape were acting again; probably they were going to complete their capture of the Marsobus. Ashby did not know. All that he knew was that the light was a thing of which he had been afraid not so long ago; now it proved to be a friend, for it gave him the chance to see his present foe. Time and time again, while the light held, he slashed at the octopus, until the brute was nothing but a ribboned remnant of its old self, while Ashby, exhausted by his tremendous efforts, slumped into the water. The dousing revived him somewhat, and he compelled himself to scramble up and stagger onwards towards the shore, reaching it just as the light-balls died away.

Strangely enough, during the battle with the octopus Ashby had not thought of his other foes; had not, indeed, had time to spare for a glance seawards. If he had he would have found that he had been standing in the water in what was really a cove, sheltered from the outside, which could not be seen into from where the ships lay off the harbour. Now, as he staggered on to the dry land, be began to realize why it was he had not been molested, or an attempt made to capture him. He had not been seen.

Fear of the rising of other fire-balls, with the chance of not being seen next time considerably uncertain, made Ashby decide that it became him, for the time being at any rate, to conceal himself and not try to move far until he had had time to get an idea of the lie of the land, which he could only do during the day-time. The last of the fire-balls, as they died away, had shown him something that he believed would provide him with a temporary hiding-place at least; a cleft in the wall of rock beyond the stony beach on which he stood. Brief though his glimpse of it had been, he had yet noted its position, and be strode in the direction of it. Well aware that the cleft did not start from the ground but was placed some distance away, he had to make sure that he was beneath it, and also to find a way by which to reach it.

Because of the darkness, he knew that he would have to take the risk of using his electric torch, which he had carried with him in his waterproof pouch. He switched it on behind the cover of his soaking jacket, cupped it in his hands so that the light from it was dimmed as it streamed out, and, throwing its beams against the face of the rock, he searched for the opening that meant so much to him. He found it after a while, and saw that, although it was some ten feet above, it was accessible owing to the broken character of the rock beneath. He turned off the light, conscious that to use it any longer while climbing might be to court discovery, and then began to make his way up relying solely upon the sense of touch. It was fairly easy to him, even although he was very nearly "all in." It was merely the undaunted courage and fine determined will of the man that kept him going until he finally reached the cleft, which he found was wide enough to allow him to got inside it.

It was then that endurance failed; and Ashby, dropping to the uneven floor of what he imagined to be merely a small cave, lapsed into an unconsciousness that had at least something to its credit, inasmuch as it was different to the coma in which he had laid during the many hours immediately following his outburst of mad rage against Appleton. It was sleep—sleep born of sheer physical exhaustion, and it was sleep that, lasting for many hours into the following day, served the purpose of refreshing him, at the same time that, by one of those strange happenings with regard to the human brain, brought back the memory of what he considered the injustice of Appleton in prolonging the journey back to Earth; and, moreover, made Ashby's mind a blank regarding what had happened from the moment when he had dropped into his first coma until that in which he found himself standing upright in the cave and looking out across the cove with just the merest glimpse of the water beyond.

"Marooned me!" he said savagely; "that's what they've done! The brutes! Must have given them something to think about!" he was looking at his bloodstained clothes, imagining them to be the token of the fight which he remembered starting. "Well, anyhow, one of 'em got a packet to be going on with. But what the deuce did they shove this helmet on to me for?" He unfastened the diving helmet as he muttered to himself. He was wondering, too, how it was that his clothes were soaked through—because the moist night air had not allowed them to dry while he lay asleep.

Ashby's mind was now as alert as it had ever been—apart from the hiatus in memory; and he was filled with anger at what he honestly believed to be his desertion by his comrades. The thought uppermost in his mind, however, was what he was to do about his own situation. He remembered that while he was in the Marsobus he had seen people on the land, and the problems that confronted Ashby were first, food; and secondly, how to evade the inhabitants, or, at best, how to placate them if he were seen and captured.

The insistence of the body for food forced him to begin his task at once; and very carefully he made his way down to the water's edge to reconnoitre the position off the land. Arrived there, he peered around the bend, and saw a number of the large vessels, some moving out to sea, others still at anchor, and lying alongside the rugged coast, not four hundred yards away, the Marsobus.

"Gee—the old bus has been taken!" Ashby breathed; for there was no mistaking the position. A dozen of the strange-looking people were on top of the Marsobus, using queer kinds of tools in their very evidently difficult task of trying to make an opening in the machine.

Ashby's first impulse was to use the automatic that he held in his hand. Actually he raised it to fire, but then lowered it again as he realized the futility of attacking in such circumstances; and also as his consuming rage against Appleton made him mutter:

He did not know, of course, that his comrades were not in the Marsobus. His natural conclusion was that they had been unfortunate in a fight with the strangers, and that the Marsobus had either gone wrong, or the enemy had, by some clever means, managed to capture it.

For some little time Ashby remained hidden behind the rocks, watching operations on the Marsobus, smiling to himself as he saw the futile efforts of the strangers; and while he was amused by this, he was wondering what Appleton and the rest must be thinking about.

"Got the wind up, I'll bet!" he muttered. It did not occur to him that they must be in very severe straits not to be making some effort for themselves; and even if it had, in his existing frame of mind, Ashby would not have raised a finger to help them. He felt that his fate was taking retribution for the evil which had been done to him; and he was content.

The most astonishing thing about the whole matter was that Ashby did not yet realize that what was happening meant his own doom, just as much as it did that of his comrades. The truth was that his brain was deranged, though he was self-careful enough to take steps towards what he considered his own safety—at the same time he forgot that safety might really be in the direction of assisting his companions. Perhaps it was his obsession. Perhaps, on the other hand, it was a scarcely realized idea that whatever the enemy might do, he couldn't conquer the metal of which the Marsobus was made—but the fact remained that Ashby—instead of doing anything to help the comrades whom he thought were in trouble—after a while withdrew from his hiding-place and made his way back to the cleft in the rock from which he had issued such a little time before.

Hungry and wet, but realizing that as far as the possibility of food was concerned matters were hopeless, Ashby's greatest concern was to remain concealed until the coming of night, when he would be able to go out and search the shore in the hope of finding at least some kind of shell-fish.

While in the cave, however, forced inactivity naturally drove his thoughts to the question of final safety, and even in his half-insane state of mind the realization came that the future looked hopeless. Believing, in the first place, that his comrades had deserted him, he could not look to them for succour; while even if they had not cast him away, under the circumstances they would be unable to do anything, inasmuch as they were evidently imprisoned in the captured Marsobus. Also it became obvious to Ashby that his salvation depended upon himself—and the Marsobus. That meant that he would have to do something to recapture the machine, and that in its turn meant that he would have to rescue Appleton and the others. It was a long process of reasoning, but it must be remembered that Ashby was still obsessed by insane rage, and what previously would have been a very obvious course for him to take, he now regarded as the one to be avoided if any other way could be found.

But once he had reached the point of decision, he became fired with impatience to be doing. He paced up and down the cave into which the gradually dying light filtered, but did not reach the extremes of it. Unconsciously the distraught man lengthened the stretch of his pacing, and it was with something of a shock that after a while he discovered that there seemed to be no end to the cave. Up to then it had not occurred to him to use his torch, his mind had been too preoccupied with schemes and hopes for him to worry about the character of the place in which he was hiding. Now, however, he pulled out the torch and switched it on. The streaming light from it showed him what, in a calmer frame of mind, he might have discovered without a light. The floor of the cave had a decided inclination. Moreover, the cave was very narrow, almost like a tunnel, in fact; carved out of solid rock. The floor was uneven, and the roof, about the height of two men, was of stalactite formation.

For a few moments Ashby stood still and flashed his light here and there, wondering what lay beyond, and whether he should risk further exploration. Finally he decided that he would go at least a short distance, and, using his torch only intermittently to show him the character of the floor in case there might be crevasses, he proceeded into the darkness. What astonished him as he went was the length of the tunnel. He had been counting the paces, and had reached three hundred without reaching the end, and the question came as to whether it was worth while pursuing his journey any longer. At a point the tunnel, instead of easing up, began to go down very steeply.

"Just a little farther," he muttered, and went on much farther than he had really intended; and then curiosity had him in its grip, and he knew that he must remain to learn what there was to be learnt.

What had happened was that of a sudden, he saw afar off, not the glow of a moving light, but of a steady brightness, which suggested either that he was nearing an exit into the open air, or that there was some artificial light down there in the depths. As he thought about this matter, Ashby decided that the latter must be the case—since the twilight was not strong enough to give so much brilliance.

Ashby went on, impelled by curiosity. Now and again he used his own light, but less frequently in case the light beyond indicated the presence of people. Carefully and quietly he picked his way, feeling by the rock-wall as he walked; and the light grew larger as he went, until at last he knew that there was need for more caution. Coolly he drew his automatic from its waterproof case and then moved forward, almost creeping, so quietly and so slowly did he go. He could see the end of the tunnel: it was as though it ended as a corridor ends by leading into a hall.

The glow lighted up the tunnel now, and Ashby was afraid lest he might be seen; but having come so far he determined to carry on. He hugged the wall and came to the arch, peered out, and gasped with astonishment.

The tunnel ended on the very edge of a pit, at the bottom of which was a city seeming built of marble. It was a wonderful sight. From the roof, which was about ten feet above the tunnel in which Ashby stood, hung what looked like a series of beautiful curtains chiselled out in marble. The walls of the pit itself, which was hundreds of yards in diameter, were of rock, with what Ashby took to be houses cut into them; while great pillars of white substance reared up from the floor to the roof, and this white substance threw back a scintillation of light as the brilliance of a mysterious light cast itself upon them.

There were houses built in rows; and the streets, all of which led to a central square, were filled with people moving towards that place. In the centre of the square was a marble-like plinth, which Ashby judged to be some twenty feet in height. It was flat-topped, and there were steps leading up to it. The people were all dressed like those whom Ashby had seen above.

Ashby had flung himself down and was watching the scene. He had forgotten everything in the fascination of what he saw, and the murmur of thousands of voices coming up from below—the pit was at least a hundred feet deep—droned in his ears.

He was held by the wonder of it, and his curiosity made him careless as to whether he were seen or not. As he watched, the crowds of people gathered in the great square and stood tightly packed around the plinth, looking up at it as if waiting for something to happen.

And when it did happen there was a roar, in which Ashby himself very nearly joined from sheer astonishment.

The top of the plinth opened as if there were a sliding panel to it, and from inside it there issued a man taller than the rest of his fellows, but dressed the same as they with the exception that he wore a head-dress that attracted attention immediately, because of its remarkable character. Ashby realized that it was made out of the head of a sword-fish, and the sword was still attached to it. The man stepped on to the plinth, and there came after him three other figures, which to Ashby's amazement, turned out to be Appleton, Mackenzie and Teddy Craig. Behind them were several of the strange people; and as soon as all were on the plinth, the panel slid back into place. The man with the head piece turned to the assembled crowd and seemed to beckon for silence, which he got instantly, and then he went on talking for a long time, every now and again having to stop because of the uproar as of cheering. He kept pointing to the three captives, whose arms were securely tied behind their backs, while their legs were free.

He watched and listened to words that he could not understand, but the grim meaning of which he grasped after a while. Suddenly the captives were seized by their guards and forced to lie on the grating on top of the centre of the plinth. Ashby had wondered what that grating could be for, but now he was to know. The prisoners were bound to it, not without a struggle. They were secured and could move neither leg nor arm. The man who had been speaking to the crowd said something to the guards, who disappeared through the sliding panel. The leader spoke to the prisoners, making vigorous signs as he did so, and the fact that Appleton shook his head told Ashby that he understood what was required of him and was refusing.

The man stamped upon the plinth, and there came an answering shout from below, followed a few minutes later by smoke issuing, from between the grating on which the prisoners were lying.

Even then Ashby did not quite realize what was taking place. It was only when the smoke gave place to a dull red glow that the full truth broke upon him.

"Being grilled, by George!" he almost cried. And to his credit, let it be said, for the time being he forgot all about his own feud with them and determined that the moment had come for him to take action.

He raised the soundless automatic and fired straight at the man who was the leader. He spun round, throwing up his arms as he did so, and then tumbled off the plinth. There was a rush on the part of the people standing nearest, and a great uproar ensued.

"Looks as though I've done it on him!" Ashby muttered grimly, as he saw the consternation amongst those who had raised the man and were examining him curiously. They dropped him back to the ground, and one of them rushed up on to the plinth and ran down through the panel. A second or two later the guards rushed on to the top, and Ashby saw that their feet were differently shod from what they had been before. They walked on to the grating and cut the bonds that tied the prisoners to it, lifted them to their feet and drove them below.

Ashby's self-satisfaction at the success of his shot was short-lived. He had known that, and relied, upon the fact of the silence and suddenness of the downfall of the leader would most likely cause confusion and perhaps interrupt the course of events. What he did not know, of course, was that the people below, or at least some of them, had experienced the effect of the silent weapons during the ensnaring of the captives on the deck of the ship while Ashby himself was lying in his coma in the Marsobus. He had hoped that they might be superstitious enough to lay the striking down of their leader at the door of Fate, as a retribution for what they were doing to their captives; but actually what happened was that they understood that in some way the fourth man who, as the fugitive from the Marsobus had told them, had been thrown overboard and then returned to the machine, was actually in the underground city.

Despite his ignorance of all this, Ashby interpreted aright the next move on the part of the people below. The great lights went out suddenly and the glow beneath the grating on the plinth was the only patch of light.

"They've tumbled to it that someone's about!" Ashby muttered; "and they're going to search. It's me for the open air!"

CHAPTER 4
Adrift on the Ocean

ASHBY realized that the people would know all about the tunnel in which he stood, and at the same time he realized that there were probably several other tunnels leading to the city, and that the enemy would guess that he had come by one of them.

He went rushing up the incline, reached the top, and then ran down to the tunnel mouth.

As he ran he had formed a scheme which he knew would, if successful, not only mean that he would escape for the time being at any rate, but would also serve to mystify the enemy.

At the cave-month he had left his diving helmet which he now put on. He placed his automatic into its case, and scrambling down the rock face, ran to the water's edge and waded out until he was able to walk beneath the surface.

Walking, as he was, beneath the surface of the water, Ashby had nothing to guide him except his sense of direction, and yet, so confident was he, that he felt he was going right. He did not dare to use the torch that he carried: the light of it would have been seen from above and the success of his scheme, in all its aspects, depended on his being able to carry it out secretly. It was to be in the nature of a surprise for the enemy.

So he went on slowly, passing here and there the shadows that signified ships, and always moving in towards the shore when he felt the sea-bottom declining outwards. The absence of his diver's boots meant that he must keep always only just below surface; and therein, of course lay a danger, though, as it was nighttime, that danger of being seen was considerably reduced.

For hundreds of yards he walked, now and again going nearer to the shore so that in the shallower water he could put his helmeted head out and see how near he was to the Marsobus. It was at the sixth time of doing this that he received the surprise that suggested he must alter his plans; until he finally came to the conclusion that, although it changed in some respects, it might still be carried out in the main.

What he saw was the Marsobus lying bathed in a blaze of light as a searchlight flashed its beam upon it, and at the shore, near which it was moored, were Appleton and Mackenzie and Craig, together with a number of people dressed in the shiny scaly clothes.

"What's a-doing?" was the thought that ran through Ashby's mind as, within two hundred yards of the Marsobus and well outside the stream of the searchlight, he stood, half-head only above the surface, and watched.

Naturally, he made no further move towards the Marsobus; the plan now was to learn what was afoot. He was soon to learn.

He saw Appleton lifted, struggling, by several of the strangely attired men, and laid, face up, on top of the Marsobus, while other men went into the water carrying ropes. Yet others straddled across the Marsobus, and within a few minutes Appleton was bound to the machine, with ropes round his ankles and his arms outstretched above his head. By the time the same thing had been done to Craig and Mackenzie—the former at the bow, the latter at the stern, with Appleton in between them—Ashby had grasped the idea. Ashby saw one of the men speaking and gesticulating to Appleton, as though he were being given a last chance; and Ashby suddenly roused to the reality of the situation and the necessity for him to take his own action.

One of the men was gesticulating and speaking
to Appleton as though givimg him a last chance.

Previously his plan had been to get into the Marsobus via the underwater "diving door," and to mystify the enemy by working the machine away from the shore, after having cut the cubic with which it was moored. That would have meant that while the enemy were searching for the man who had killed the leader in the underground city, they would be made aware that after all the strange machine was being operated. That, however, would have meant that Appleton and the others would have to be left; which, after all, Ashby did not mind, except that his own safety in the end depended upon that of his comrades.

Now, however, he realized that not only did he stand a chance of getting into the Marsobus, but also of effecting the rescue of his companions—if everything worked as he hurriedly thought it out.

He stepped back into deeper water, and walked towards the Marsobus, troubled mentally as to whether he would reach it before the enemy cast off the Marsobus—because Ashby had clearly understood that the intention was to send the craft off on the tide—with its strangely prisoned crew aboard.

Ashby hurried as well as a man in such circumstances could hope to hurry, and although once or twice he had to go to the surface, he actually did reach the Marsobus while it was still moored. When he came within the down-glare of the searchlights, he had to be careful lest his form be seen beneath the surface. It was the shadow of the Marsobus above that told him he had reached his objective.

He knew that the most critical moments had come. He must be careful about getting into the Marsobus. He walked beneath it, sheltered by its great bulk, until he reached the place where the diver's door was situated. Unable to see, and afraid to use his torch, he had to rely upon his sense of touch and his knowledge of the Marsobus; neither failed him, and at last he found the spot at which the door could be opened from outside. He performed the necessary work—and the outer shell of the Marsobus slid open. The next step was to get into the cavity; and this he did by grasping the rails that were inside and pulling himself up by a great effort. He felt the Marsobus rock and wondered whether the people above would be suspicious. He need not have worried, for at that moment they were cutting asunder the hawser by which it was moored, and as Ashby found himself inside the cavity and slid the door to, thus shutting himself in, the Marsobus was freed. He did not know that. All he knew was that he was inside, and a groping hand touched the mechanism that slid open the inner door and he was once more in the Marsobus, his immediate task accomplished, but others awaiting him.

He stood up, the water draining from him in a pool. He removed the helmet and stretched himself.

"So much to the good!" he said aloud, and there came an answering voice that made him start; he had forgotten the prisoner he had left behind.

"Gosh, I wonder what the deuce is that?" he said. And even then be failed to recall the incident immediately preceding his narrow escape from death in the clutch of the octopus. His mind was hazy and uncertain still.

For the moment he had nothing to do. He decided that for a little while it would be unwise to get the engines working. He must wait until he felt that the Marsobus had got sufficiently far away from the shore for anything that he did not to be noticed.

Caught by the tide, the machine was drifting off into the darkness and the mist, and Ashby, himself soaked through and chattering with the cold, wondered what Appleton and the others could be feeling like as they lay looking up into space, helpless to save themselves, and not knowing that there was help of any kind near at hand.

"They're going to be mighty surprised when they see me!" he chuckled, and there was only a grim humour in him. "They'll think I've come to get my own back. Wouldn't be a bad idea to show myself and then let 'em stay where they are for a little while longer! By George, I think I'll do that!"

Very cautiously he slid aside one of the window covers, knowing that the absence of light in the Marsobus would make it possible for him to see without being seen; and he found that although there was still the glare of light that told of the searchlight, it was not fixed upon the Marsobus, which evidently had made good progress on the bosom of the water.

"A little longer," Ashby muttered; but he did not shut the window this time: remaining by it and peering out across the waste to the rapidly dimming lights of the shore and the ships, until at last he judged that it was safe for him to act. Although he closed the windows he slid open the trap-door in the top of the Marsobus, and then switched on one of the lights; then ran up the steps that led out.

"What the deuce is that?" he heard a voice say—the voice of Appleton issuing from between teeth that chattered through the cold. The light was thrown up like a spurt, and it was this sudden glare that had made Appleton exclaim.

"Must be Ashby—thank goodness!" said Mackenzie's voice. "Though how he got free I don't know. Hallo—Ashby!"

"Yes—all> right!" Ashby almost snarled. "You go and maroon me, glad to be rid of me, and now—now—"

"I say, Ashby, old chap—what are you talking about?" Appleton broke in, utterly astonished. "You've gone mad—to think that we deserted you and—Look here, cut us free and then we can talk about things."

"Why should I? D'you think I want> to talk about things?" Ashby said tauntingly. "You can stay there and freeze!"

He stepped back into the machine and actually slid the door to above him. And his amazed comrades were left to make the best of a business that they could not understand.

"Mac," said Appleton, "I'm beginning to see light, I think. Somehow Ashby managed to get free—likely enough he was captured and escaped. Also, I'll bet it was he who knocked out that fellow in the underground city—though how it all happened I can't guess. Then he must have come back here—did you see—no, you couldn't where you are. But I did. He's dripping wet at this very moment, and I shouldn't be surprised if we find that he got into the bus through the diving door while she lay moored."

"Doesn't seem as though it's going to do much good for us however he got in," Craig put in. "What's he mean about being deserted?"

"Can't imagine—Unless he came round and found himself bound, and was cut free by the enemy. Poor old Ashby. I'm afraid his mind's gone a bit rocky. I . . . hallo—he's got the engines going!"

It was a fact that the Marsobus, instead of drifting as she had been doing, was now pushing a purposeful way through the water; and as she was moving at a very rapid speed, the three men bound to her, in as grim a situation as ever men have found themselves placed. Were well-nigh frozen by the rush of wind.

Although they did not know it, Ashby was sitting in the steering cabin, with the window open and peering across the waters, on the qui vive against colliding with anything; and he was enjoying himself. He had a further little scheme he was going to play, and he proceeded to do so. He ballasted the Marsobus slowly, and she began to submerge. The water lapped up and about the three men outside, and Appleton, who had been the first to sense the new motion, but had been afraid to mention it, now yelled out with fear.

"He did it well!" Appleton said with a shiver. "I wonder—Here he comes!" as once more the door opened and the light streamed out.

"Not so mad—not so mad!" Ashby chuckled. "I'm out for a bargain with you. You wouldn't agree to go straight home before; but now you've got to agree, or else you'll never go home at all. I'll just close the trap and submerge! It's up to you! I'll take the risk of being able to get the old bus back!"

The ultimatum thus presented to them left the three bound men speechless for a while; they could only stare at Ashby as he stood, half in and half out of the Marsobus, his rugged figure thrown into bold relief by the light streaming up from within.

It was Appleton who found his tongue first—and that only because Ashby rapped out:

"Look here, old chap," the Professor said, "you've got the master-hand in this game; and, after all it's not altogether fair for you to play it when the rest of us are—I thought you weren't well—you've been such a good fellow all through, and—"

The unexpectedness of that was sufficient to make Appleton, for one, laugh, even in those circumstances—it was so ridiculous, and Ashby himself joined in. What the effort would have been—whether that momentary and involuntary sense of humour would have had any favourable result—must be left amongst the unknown things; for, just then, there came an almost blinding glare of light upon the Marsobus—and everyone knew that it was a searchlight from an enemy vessel.

"Quick, Ashby!" cried Appleton, first to grasp the meaning of it. "We'll all be snaffled. Free us and get us in—now!"

With one of those strange, mental freaks that were characteristic of him in his present state, Ashby, instead of seeking his own safety—which he could have found by going in, abutting the door, and submerging, quite heedless of the fate of his comrades—whipped out his knife, laid hold of Appleton, and slashed the bonds that held him.

"Free Craig!" he said crisply. "I'll see to Mac!"—and, bathed in the light from the unseen ship beyond, the pair crawled along the Marsobus in opposite directions, and carried out the work of setting their companions free. It was a most dangerous and nerve-racking business—only to be compared with the crawling, slipping journey to the opening where safety lay. The light was worrying, blinding, in its intensity, and growing more brilliant every moment; while Appleton and Craig and Mackenzie—who knew—were obsessed by the idea that at any second there might be re-enacted the incident when the Marsobus had been caught in the mysterious lighted nets; besides which, there was the over-present likelihood of sliding off the Marsobus. Actually, Appleton, who reached the centre first, decided that safety for the others probably lay in dropping off into the water; and he told them so.

"I'll let over the ladder," he said, "on the other side. Now, then, off!"—and as one man they all three obeyed, while Appleton reached down and grabbed the rope ladder, which he flung overboard.

"Find it—I'll go and set the engines working!" he then shouted; and without waiting to learn whether they had understood him—he had little doubt they had—he dropped into the Marsobus, and before ever Teddy Craig, first up the ladder, was in the machine, the engines were throbbing their soft purr.

Craig, standing on the steps within, head and shoulders above the hull, saw a row of lights dart into sight; they were, he realized, lights on the ship from which the searchlight was streaming, and the vessel was now much nearer at hand.

"And next—the nets!" he cried aloud. "Hurry, you fellows!—and, as answering calls came from below, he shouted down to Appleton:

And Appleton swung over the starting lever, the Marsobus turned smartly, and was then going away at a speed that threatened to dislodge the two men clambering up the ladder down her side, while Craig had to hang on for all he was worth.

Mackenzie came up first—and Craig made way for him to enter; immediately afterwards Ashby came, and, getting in, drew up the ladder after him, sliding the door to at once.

"Dive for it, Chief!" Craig rapped instantly; and the Marsobus began to submerge as Appleton called out:

"Right oh! We're going!" and switched off the light, knowing it would be seen from above. "Mac—I want you, quickly!" came Appleton's voice then; and the engineer sprang into the cabin where the Professor was. "Eyes on Ashby—and an automatic—if you can get one without him seeing," Appleton said softly as soon as Mackenzie was beside him. "I'll call him in, while you go to the locker. Quickly!"

Mackenzie disappeared, and Ashby, at a call from him, went in; and Appleton, professing to be engaged for a few moments, kept him waiting until he heard Mackenzie return. It was then that the Professor spoke, while the Marsobus was descending lower and lower.

"Thanks for getting us out of that mess, Ashby," he said. "No—wait a moment while I tell you something," as Ashby seemed about to speak. "There's evidently some misunderstanding."

"No misunderstanding," growled Ashby, refusing to be silenced. "I understand clearly enough that you put me ashore and—"

"That's just where the misunderstanding has come in. What's that man doing there?"—and he pointed to the bound captive, the captive whom Ashby himself had tied up, but remembered nothing about because of the hiatus in memory regarding what had happened between the time when he had gone off into unconsciousness before Appleton and the moment when he awoke in the cave.

"I don't know who he is," Ashby said. "Didn't you catch him, or—" he was bending over the man. "That's my handkerchief tied on to the rope to make it long enough." He drew his hand across his forehead, as though trying to recollect things. "You must have done that!"

"Nonsense!" said Appleton. "Now, listen, Ashby . . . hallo! we've touched bottom. We'll rest here awhile," and he shut off the engines. "Here's all I know about things: You had a touch of fever, lightheadedness, and all that sort of thing. You tried to do for me, but we managed to get you down. Then, because we were going ashore, we decided the best thing to do, in case you came round and were still queer, was to bind you up so that you couldn't come to any harm. We left you in your bunk; and after no end of trouble of various kinds, we went aboard one of the ships belonging to the people here. Those people played dirty—and they seized us. I don't know what happened to the bus then; but we were taken ashore and made to go down to an underground city, where we were left some time. Later on we were fetched out of the prison or whatever it was we were in and taken to the bus. As far as I could make out the crowd wanted us to show them how to open it. We refused, because we couldn't afford to risk their monkeying about with the works. We couldn't understand why it was closed, because we had left it open; we imagined that they had shut the door accidentally. Then, when we refused, we were taken back to the Underground City and tied on to a grill and—"

"I remember that," put in Ashby. "I shot the leader—" and then he launched forth into an account of things as far as he remembered them.

"How did I get on the shore in my diving helmet?" he demanded when he had finished.

"I should think," Appleton told him, looking curiously at him, "in the same way that you got back to the Marsobus a little while ago! You say you remember nothing from when you were trying to 'get me' to when you found yourself in the cave. Well, it's pretty clear to me that you've lost your memory of that time. Also, that probably enough this prisoner came into the Marsobus and unbound you, and that you managed to get him.

"What happened then, goodness knows, except that you must have put on the helmet and got out of the bus. The blood that was on you? That's a mystery—probably you had a scrap with this man; see if he's wounded."

Ashby, still looking dazed and unbelieving, moved over to where the captive was lying and examined him, but, finding no wounds sufficient to have caused the amount of blood that had surprised him, he was more puzzled than ever.

"Chief," he said quietly, going back to Appleton, "will you give me your word that your yarn is true? That you didn't desert me?"

"Of course, old chap," Appleton told him. "Why should we have done a thing like that—after all we've been through together? The trouble is that you're ill—some day you'll remember things. Meanwhile, are we going to be pals again, or are you dead set on forcing us to leave here? You know what I feel. I'd like to stay. What about it?"

Ashby stared at him, it seemed, with unseeing eyes; very plainly he was having to fight a battle with himself; and Appleton and the two others waited for the outcome. As far as Craig and Mackenzie were concerned, their only interest was one of desire for sheer adventure and the novelty of the whole affair. But, as far as Appleton was concerned, the position was different; there he was, a man of science, who had accomplished a thing beyond even the dreams of most men, with the chance to collect information about a mystery planet.

Therefore, Appleton's tension while he waited for Ashby's verdict, was very great; and, therefore, it was with an intense relief that presently he saw Ashby step towards him, hand outstretched, and heard him say:

"Chief—I'll take your word for what you say; and—and—I'm willing to stay."

The tension was snapped. Appleton took Ashby's hand and wrung it fervently; Craig and Mackenzie crowded around, and within a few momenta the quartet were on the old terms of fellowship.

"Well, fellows," said Appleton suddenly, "I don't know how you feel, but I'm as hungry as a hunter; I guess we'll feed!"

The suggestion was hailed with enthusiasm, especially by Ashby, whose long fast had rendered him ravenous, and in a short time they were all enjoying a good meal.

"I suggest," Appleton said presently, "that hereafter we each carry a portion of the concentrated food we brought from Mars."

This suggestion was naturally agreed to; and, to save trouble later, each there and then received a share of the remarkable food that the Martians ate just before they went into the winter sleep, and of which the adventurers had been given a good supply before they left their planet.

"There's no move. We're going to get some sleep. We'll take turns at watch, of course, and we'll wait until to-morrow before doing anything else. What I suggest is that we leave the island where we've got into so much trouble and go on a flying tour over the planet and try to see just what sort of a place it is. What do you say?"

CHAPTER 5
Beneath the Barrier of Ice

EVERYONE agreed to a tour of exploration, and when, the next morning, they awoke refreshed, it was to prepare for one of the most remarkable voyages they had yet undertaken.

During the night the Marsobus had lain on the sea-bottom, quite motionless and without lights, lest even at the depth at which she was submerged the enemy above should become aware of her presence. The prisoner, who had been fed, was kept bound, and Appleton had not wasted any time on trying to question him, for the simple reason that that was futile, because of the language difficulty. When the morning came and the adventurers were ready to begin their journey of exploration, the problem was what to do with the captive, and a council was held over him.

Mackenzie was for rising and pushing up the periscope to see if they were anywhere near land, and if so, letting the man go; but Appleton, after some consideration, decided that perhaps it might be as well to retain him.

"You never know," he said; "we may lose our bearings and the fellow may be able to help us find 'em; and it will be some advantage, possibly, to come back this way—one never knows; although I'm not very keen to hit up against these people again. What I want to find is a place where I can work out the trajectory for the return journey, when we decide to make it, and for that work solid land is the best place!"

"Please yourself, Chief," Mackenzie grunted. "The only thing is that the fellow's going to be a wretched nuisance. Someone's got to act as dry nurse to him all the time, 'cos we can't have him loose on the bus."

"That's so," said Appleton; "but we'll risk the trouble. Hallo—what's this?" He was looking in one of the lockers as he spoke, and withdrew the bomb-shaped thing which Ashby had placed there when he had found it two nights before. "Never seen that before!"

"Well, it must have got there somehow, and—see, that fellow doesn't like the look of it!" Appleton exclaimed. He had been handling the ball and nearly dropped it, and the prisoner had started in his bonds. "Do you know, Ashby, I believe that when you were aboard before you must have picked up this thing and put it in the locker out of the way. And I believe, too, that it's not a very nice kind of thing to have about—else, why should that chap jump like that? It may be useful to us, because we've only got about one shell left, and we may want that one of these fine days. Thank goodness, anyway, that we've got plenty of small ammunition."

He turned away and put the bomb, or whatever it was, into the locker again, and started back as, opening another, he made the discovery that there were no shells at all.

"But there were some!" he exclaimed. "The mystery's growing deeper, though, at the same time, it may be clearing itself up. Ashby, do you remember that bomb, and do you remember whether you had anything in the way of a scrap and used the gun?"

Ashby rubbed his forehead again and again, as if trying to recall things, but shook his head as he said:

"Chief, I can't remember anything about either. As far as I know I've never seen that ball before, nor have I used the gun since we were on Mars."

"The matter settles itself, however," Appleton decided. "You must have done both—none but one of us could have fired the gun, and I haven't, and I know that Mac and Craig hadn't any more chance than I did after our little affair before we were captured. You have had a lapse of memory for the particular stretch of time. Anyway, we can't do any good by arguing about it. Let's be doing things that may be useful. All to stations!"

To stations it was, and in a very short time the Marsobus was within a little distance of the surface, her periscope was shot up, and Appleton examined the reflection in the mirror.

"No land, all sea," he reported after a while. "And, fortunately, no ship in sight. We'll go up and then take the air while we can."

So the Marsobus was taken on to the surface, the necessary mechanical adjustments were made to enable her to rise into the air; and then she rose on her helicopter until she was a thousand feet up, and the men in her were looking down upon a sunlit sea, seemingly as calm as a mill-pond, and boundless.

"There must be a north and there must be a south to this world," Appleton said presently. "I'll find out where they are, and we'll make for one of them. Then we shall have some kind of fixed point."

He spent some little time at calculations and measurings and observations, during which time the Marsobus hovered in the air—and the captive, whom Mackenzie had, for the sheer fun of the thing, taken to one of the windows, looked down at the waters with amazement written on his face.

"It's fairly certain, fellows," the Scotsman said after a while, "that those people don't know anything about flying machines; they may know how to build ships, and bonny ones, too; but they're evidently ignorant of aerial transport, else this chap wouldn't look so surprised."

"That's good—if it is so," Teddy Craig said. "It means that when we're in danger, we've only got to come up and we'll be in safety."

"Ready, you fellows?" came Appleton's voice at that moment. "If so, we'll be off. I've got the direction, but, of course, know nothing about the distance. Anyhow, it's somewhere to make for, whatever there may be on the way; I'll pilot—the rest of you can do what you like. What about trying to get into conversation with Mr. Prisoner? Sort of take everything he's got about him and sign to him to see if he says anything that can be taken to be a name."

It was a strange proceeding and a long one, but, fortunately, there was plenty of time in which to do it, for the Marsobus travelled for thousands of miles during the next four days without a sign of land in any direction: and for all that time one or other of the adventurers was engaged in painstaking sign-questioning of the captive. The result was not so bad as might have been expected, for they managed to extract from him what they, at any rate, believed to be names for certain objects: the metal knife that he carried, the various clothes that he wore; the whiskers that could hardly be said to have "adorned" his face; the broad, metal sword that he once had carried, but which was lying beside him when he was found; the ball which was in the locker—he cowed from before that when it was brought to him; the water below; the vast space of heaven above; himself, and many other things—to all these he gave, when it appeared that he understood what was expected of him, "sounds." Appleton insisted that every sound should be "put down" on paper, as nearly as it could be done, with the name of the object against it, and, to make sure that they were on the right track, every now and then a sudden question, containing one of the words, accompanied by a gesture, would be thrown at the captive, who immediately glanced towards the particular thing. For his part he had thoroughly grasped his captors' desire, and was quick to take advantage of it: for Appleton was amused, as well as pleased, when, suddenly, on the fourth day—he had of set purpose kept the prisoner without food for several hours—the latter ejaculated "words" for food and drink; and, on receiving both, expressed on his face the pleasure that he felt, perhaps not only at receiving what he wanted, but at having been able to make himself understood.

"Verra guid," Mackenzie said. "But even so, Chief, it'ull take us aboot a hundred years to learn the lingo."

"But even a word here and there may come in useful some time," Appleton told him.

They were indeed to find that the work which had been done during those few days had not been useless, but meanwhile the concern of Appleton was to get "somewhere." The interminable stretch of water and the mileage covered by the speeding Marsobus was extremely great—was monotonous; and yet it was confirming the Professor in his belief that he was in a Water World, and the only explanation he could find for it was that it was a planet, that had experienced some great catastrophe that had caused an immense inundation—and that in itself would account for the sudden appearance of the planet in a position in space where there had been nothing before. It was in the course of its orbit that it had whirled itself there, but the fact that it had remained so long proved that it was travelling relative almost to the earth, although as it had arrived, so in process of time and motion it would pass.

The atmosphere envelope was like a cloak of invisibility to the planet, rendering it invisible except when it happened, as it now had, that the planet came between two points where it was customary for observation to be made; and it was through this that Appleton had discovered it, to his great perturbation while on Mars, as he reflected now while he was piloting the Marsobus over the waste of waters.

For four whole days he had been doing this, bringing the Marsobus down during the nights, and for safety's sake submerging, lest a ship should run into them; although, as a matter of fact, during those four days no sign of a vessel had been seen. That fact had puzzled Appleton not a little. It seemed a strange thing that with so many big ships lying off the island at which they had alighted, there should be none moving on the waters, and Teddy Craig, with the illogicality of youth, had suggested that perhaps there was only that one island in the whole planet.

"Nonsense, Teddy," Appleton said. "People wouldn't build all those ships, and such big ones, just for the sake of hugging their own shore and—"

"But it isn't a very big shore, Chief," Craig suggested. "You'll remember that when we were at a great height we could see that it was an island we were over, and, well, populations have a habit of getting larger, and the people must live somewhere! Why not in ships, if there's no land for 'em?"

"Why not, indeed?" Appleton agreed; but he was grinning. "One thing against the idea is that those ships have a good turn of speed on them—and if they're only intended for floating homes, they wouldn't need that. They'd probably become anchored; sort of piers or something like that. No, depend on it, there must be other islands—if not big continents. A drowned planet I've called this show, but even a drowned planet may have some tidy large spaces of dry land to it, and I expect to find some soon."

"Then I'd like to see a patch," the younger man said ruefully. "And when we do we get to the pole?"

"Don't know," Appleton told him. "But haven't you noticed that the air's been getting keener, and the days shorter? And last night I noticed when we were down below that the water was decidedly colder: the thermometer said it was several degrees lower in temperature. I'll test it again to-night and—Hallo, there's a ship!"

He broke off and pointed excitedly to a white splotch on the horizon, just visible to the naked eye; but when Craig brought him binoculars to bear upon the spot it was to report:

It did not need more than a glance to prove that Craig was right in what he had said, and Appleton was gratified to know that his deductions had been correct.

"That means," he said, "that we're nearing the polar region, and a few hours' travelling at good speed will, or ought to, see us there. We'll go down for the night and start off again on the last stage to-morrow."

So down again into the depths the Marsobus went after Appleton had made his tests. This night Appleton went lower because the proximity of icebergs might mean a collision with the tremendous underwater substructure of the huge frozen castles.

The periscope was called into use when, next morning, the ascent was made to the surface, and it was just as well; for the Marsobus, which had been proceeding under water during the night with her searchlight working, had clearly got into the path of icebergs, several of which were to be seen. Appleton got her up without fouling any, and presently the machine was in the air, surging forward at a terrific speed which by the evening of that day carried her, as the signs had portended, into the polar region.

"Land!" Craig cried suddenly, pointing to a wide stretching line in the far distance, but Appleton said, after inspection through the glasses:

"Not land, Teddy, but ice. It's too late this evening to risk alighting on it, so I reckon we'll go down to the water again and wait until the morning. It'll be a deep dive, too, for we don't want to be bashed between bergs with a few hundred thousand tons of ice in 'em. Even the old bus mightn't stand up against that!"

Appleton descended while yet many miles from the ice barrier, and during that night he himself was the pilot while the Marsobus was kept on the move, her engines working only just sufficiently to keep her going at her lowest speed. Even so, when the morning came and he pushed up his periscope, Appleton found that he had run into some danger for which he had not provided. Instead of the periscope mirror reflecting a seascape, there was no image on it at all. It was just a blur, and he drew in the periscope thinking it must have become fouled with something. To his surprise he found that this was not the case. He said nothing to his companions, but tried again, with a like result. He could not account for it. There was, however, the consoling fact that he was still in a waterway, free of ice to the depth to which he was lying; for his depth recorder told him just how far down he was, and he knew that his periscope had gone above surface. What the explanation of it all was he couldn't guess. He felt that it was up to him to tell his comrades now, and he did so, saying in conclusion:

"Carry on, Chief," Mackenzie said, taking the responsibility of spokesman for the rest.

So the water-ballast was let out at the minimum rate, and the Marsobus began to rise so gradually that her ascent was scarcely perceptible; only the figures on the dial told the tale of her movement. Appleton was at the periscope mirror the whole time, but always there was that same unmeaning blank, even to the moment when the Marsobus was only a few feet below surface.

And then the machine broke surface, and her streaming searchlight swept along the water. The men at the uncovered window stared out and saw to their amazement, that they were not on the open water, but in a channel cut out of solid rock, and roofed with rock, too.

"Phew!" breathed Appleton. "That's done it! We've simply run into a submarine way beneath land, and that land is beneath the ice field that we saw in the distance just before we left the air!"

"Well, we got in, so I guess we can get out again, Chief," Ashby said. "And we'll go out on the surface and not below."

"Of course," Appleton agreed; but there was that in his voice that made his comrades look quickly at him.

"Oh, nothing—except—" Appleton hesitated. "Except," he went on again, "that it seems a pity to go back before we've seen what this thing really means. I—"

"I just do!" Appleton exclaimed. "Remember that other underworld we were taken to?"

"Where they nearly turned you into grilled chops," Ashby said, with a grin. "Get on with it!"

And because it was Ashby who said it—the old Ashby, recovered from the fever-madness, but still with the memory blank—Appleton knew that he could do what he wanted to do. The two others would not disagree.

"I think we'll go with a look out above," he said quietly. "Mac, you'd better steer, while I'm outside. Go at about half a knot; it'll be safer."

"Right oh!" the engineer said, and a few moments later Appleton was standing half out of the Marsobus, peering into the vivid whiteness thrown by the searchlight as the craft crept forward.

Weird and uncanny it was, as silent as the grave; but the singular thing was that Appleton had no difficulty in breathing. He had half expected that he would have to wear the oxygen helmet and make his comrades wear theirs; and he was agreeably surprised to find that it was not necessary.

Appleton noticed that the water was flowing inward, like a tidal river, and it was not long before he realized that it was rising. The Marsobus, riding on the surface, was gradually getting nearer to the roof, which was, however, still some ten feet above the surface; but the fact that soon it might happen that the whole channel would be filled with water did not alarm the Professor, because he knew that when necessary he could slide to the door of the Marsobus and submerge, and either proceed under water, or keep the Marsobus with just sufficient power to maintain relative position until the tidal flow returned and left the way clear to proceed.

As the Marsobus made her way onward, however, Appleton presently observed that the water had ceased flowing with it, and, after a time of observation, he came to the conclusion that the tidal flow had reached its height.

"That makes it easier, anyway," he said to Craig, who had been standing with him for some time, watching the passing scene of artificially illuminated splendour. For that channel in the rock threw back in a radiance the brilliance of the searchlight. It was as though the rock were studded with gold and gems; and once or twice Appleton, interested more than he cared to show, called down to Mackenzie to stop the Marsobus, his voice ringing eerily in the till then silence and booming back at him. He chipped at the rock, reaching over perilously to do so, and examined the trophies that he thus acquired.

"Gold, Craig," he said once; and "Rubies," he said another time. "The whole place is a treasure house. As a matter of fact, Teddy I've a feeling that this channel is not a natural one, but artificially made—sort of mine working. Probably the miners, heaven alone knows how long ago they lived, were caught in a great catastrophe. If that is so, we haven't discovered much, except old flooded workings."

"Well, we may as well go a little farther, after coming so far," Craig said, and Appleton only smiled; for his intention had been to go as far as possible.

There was something fascinating in the very theory that they were thus travelling through a channel cut, probably by men, thousands of years before. But it was only theory as far as Appleton was concerned, until after several hours of that slow motion the Marsobus arrived at a place where the channel branched off to right and left, and, to the amazement of Appleton, had a sort of funnel in the roof. Pitch dark it was above—and not even the up-flung glow of the portable searchlight revealed the limit.

So the Marsobus passed across the intersection and moved, as slowly us before, up what seemed the main channel.

Black as the Pit still, apart from the searchlight, was the passage; sheer-sided and higher-roofed the farther it went, and the monotony of it grated upon the nerves—at least upon those of Teddy Craig as he remained by the side of his Chief.

"Let's cut it out after all," the younger man suggested, but Appleton persisted in going ahead.

"Never know what we may hit up against," he said, and his persistence was justified from his point of view at any rate; for after a while longer of slow journeying, there occurred a broadening out of the channel. It seemed for all the world like a miniature lake with four rivers flowing into it, and the amazing thing was that instead of straight walls with the water lapping against them, there was what looked like a towing path all around the lake; while the searchlight, thrown first down one of the side channels, then down the other and afterwards straight ahead, revealed the fact that there were similar paths along the edge of the water. They looked like artificially cut shelves in the rock, raised some feet above the surface of the water.

Appleton called for a stop after, by his guidance, the Marsobus had been worked alongside one of the paths, and he stepped out bent on inspecting what he believed to be something more than Nature's handiwork. It didn't take him long to come to the conclusion that there was soundness in his theory. He walked around one segment of the circular path, the searchlight throwing his shadow gaunt and eerie, and giving him light enough for all that he wanted to see.

He called for the light to be thrown up the right-hand off-channel, and its beams splashed upon the concave of rock as the channel made a bend some two hundred yards ahead.

"Turn into the channel," he called out, and Craig gave the word down to Mackenzie, who obeyed. Appleton marched along the flat ledge, keeping pace with the Marsobus until the bend was reached. Then, as the searchlight was swept down the further stretch beyond, Appleton peered round; and what he saw gave him food for thought and conjecture. The path had been broken away—it ended at the bend on both sides of the channel; but farther along instead of a path there was a broad stretch of what was no doubt rock, with the water running through it. From the roof hung granite-like icicles, and from the floor uprose curiously carved pillars that did not reach to the roof above.

"Stalactites and stalagmites!" Appleton said. "This channel must be simply thousands and thousands of years old, for those things form only by fractions a year. Besides—good heavens, what's that?" The light had shifted a little and was resting on a great stalagmite many yards away; a stalagmite that certainly could not be as Nature had fashioned it. For, standing on one side of the waterway, it was formed into the shape of a hideous looking monster: looking across the water and having one arm extended. In the hand there was what looked like a sword: a great, weighty and businesslike looking weapon, that was held across the water as though ready to fall upon anything that dared to try to pass beneath its threat.

On one side of the waterway a stalagmite had
been formed into the shape of a hideous monster.

CHAPTER 6
In the Grip of the Torrent

"WHAT can it mean, Chief?" Teddy Craig breathed as, transfixed, he stared at the idol gleaming in the lights. "People—"

"Of course," came Appleton's reply. "At some time there must have been people; statues like that don't get formed by accident. Looks to me as though it must have been carved there before the water rushed in, because, arguing from its appearance, it was a sort of guardian of that channel; probably there was a mechanically controlled idol which worked by the pressure of anyone walking on the rock—which must have been level with it in those far-off days. It's obvious that it wouldn't be operated by anyone or anything passing through the water. On the other hand, there may be nothing mechanical about it; it may be simply an image commemorating something, or an ordinary idol. Queer, isn't it, how one finds the instinct of worship?"

"I think we'll go up past the statue," Appleton decided. "One thing is certain: at some time it must have denoted that something lay beyond."

So, at his instructions, Mackenzie worked the Marsobus up along the channel towards the idol, and, upon arriving within a few feet of where it stood, Appleton called for another halt. He landed on the rock on which it stood, and Craig followed him. Together they examined the idol, and it was while they were doing this that Appleton noticed that the water flowing beyond it was not deep. It was, in fact, very shallow—so shallow that he was afraid, there would not be enough depth to allow the Marsobus to proceed. With the searchlight making a blaze Appleton, curious to understand why there should be this difference in depth when the water was flowing in>, peered beneath, and made the discovery that actually the water in the farther channel was flowing outward; it was really a river which had carved itself a way through the rock.

"That's very remarkable," he said. "The tidal water courses up here, at any rate; and I'm afraid to risk driving the bus through because of the propeller, which may be damaged on the rock beneath that river."

"Well, I'm anxious to see what's beyond, but there's no way up except through the water; that being so, it's a case of wading. The water's not too deep for that, and I'm going to do it."

"You may," was Appleton's reply. "But we'll both take an oxygen mask with us, because there's no knowing what sort of atmosphere we'll run into. Go and fetch 'em, Teddy!"

Craig was off back to the Marsobus like lightning, and returned with the two masks, which they did not put on for the time being.

Appleton had one leg bared to the knee and was carefully taking the depth of the water, which actually come almost up to the hip.

Craig nodded, and a moment or so later the pair of them stepped into the water, waving a "Cheerio" to their two comrades who were watching them from the top of the Marsobus. But they had not proceeded two feet before something happened. Appleton, who was leading, was just beneath the outstretched arm of the idol and was still shaking a hand towards the Marsobus, when Craig let out a terrific yell—and pushed the Professor forward, sending him sprawling into the water, he himself leaping back on the instant.

And the great arm of the idol fell, and the sword in the hand threw up a spraying splash of water as it dropped into the water, an inch or so from where Appleton was floundering.

Almost simultaneously there came a roar as of freed waters, and in place of the slowly moving river there was a raging torrent. Both Appleton and Craig were caught in it before they realized what had happened; and Mackenzie and Ashby, in their places on the Marsobus, were chilled to the heart as they saw their comrades overwhelmed.

The great arm of the idol fell; in place of the
slowly moving river there was a raging torrent.

"Don't know—but sling out the ladder!" cried Mackenzie, "and move the old bus nearer. She can stand it!"

Ashby flung the rope ladder overside, and Mackenzie had the engine going powerfully enough to keep the Marsobus steady against the rushing water; while Ashby clung to the ladder, peering into the water for signs of the engulfed couple.

And he saw one of them—saw the white face of Teddy Craig. Only for a moment, and then it went beneath the water—only to come up again; and Ashby saw that the youngster was battling courageously to cut across to the Marsobus.

Mackenzie responded quickly enough; and Ashby, clinging to the ladder with one hand, reached out a moment, or so later and made a grab at Teddy as he swept by. The surge of the water put a terrific strain upon Ashby, but somehow he managed to hold on and so dragged Craig to the ladder which Teddy seized, and so hauled himself to safety.

"Ay, lad—but I can't see him!" Ashby said. "Can you get you down and work the searchlight?"

Almost exhausted though he was, Teddy made no bones about doing this, for he knew what Ashby wanted done. The searchlight, till then thrown only in one direction, must now be worked to and fro to assist Ashby in his search for the Professor. But, although the rush of water had ceased, as if a reservoir had burst and hurled its whole contents out, there was no sign of Appleton; and though, the Marsobus being brought to a standstill a few yards from the statue, its sword uplifted again, and all three men shouted loudly and long, no answering call came.

They looked from one to the other, perturbed and disconsolate—nay, more than perturbed, for the loss of their leader was a terrible blow, the full significance of which thrust itself upon them with appalling horror; yet neither dared speak the words that hung on quivering lips.

For what the loss of Appleton meant was that they were lost, not merely in this submarine world, but in the drowned planet itself, for they could not, even if they reached the surface again, leave the planet, because they knew not how to work out the trajectory for the journey back to the Earth! They were doomed to stay there, for the same thought was rioting through the minds of them all, that it was a better fate than to risk the venture into the vast infinity of space without the assurance of reaching Earth. They realized now, more than they had ever done before, how dependent they had been upon Appleton; and to Ashby there came back a resurgence of the old bitterness.

"The fool!" he cried. "The fool! If he'd done as I wanted, this wouldn't have happened! I—"

"Stop that, Ashby!" Mackenzie commanded. "Let's play the man, anyway! Even now, too, he may turn up. That rush of water may have taken him far down the tidal run, and I suggest we go back and hunt."

"Any old fool thing will do now," exclaimed Ashby. "It's the end, at any rate, and nothing matters. Do what you like!"

Automatically, Mackenzie took command now, and without another word of reproach to Ashby he began to pilot the Marsobus back the way they had come, with Ashby on top, and Craig working the searchlight. The machine moved very slowly, the light splashed on every yard of the way, and Ashby shouted until he was hoarse, but without avail. Neither sign nor sound of Appleton was there. They did not go back the whole way because, as Mackenzie suggested, it was likely that Appleton, if conscious, would be able to make a landing somewhere. Failure, however, to find him left the adventurers in a quandary as to what to do, and it was thrown upon Mackenzie to make the decision that they should go back towards the statue and lie there, in case Appleton should turn up.

Arrived there, the Marsobus had not laid ten minutes before her disconsolate crew received a shock that sent them tumbling back into the machine, closing the door after them.

"What—are—they?" The words trembled from Craig's mouth as he pointed an unsteady finger through the window to where swarms of white forms were swimming.

It was not to be wondered at that Craig, no less than his comrades, should be amazed and stare at them, for these figures, each of which carried a knobbed or spiked stave, seemed to be those of men who were not wholly men. Their bodies were white and, seemingly, naked—although closer inspection revealed the fact that from the waist down they were encased in shimmering "tights"—almost the same as those men whom the adventurers had met earlier; and they knew that these coverings were made from fishes' skins. The heads of the strange people were human enough, but with the difference—quite plainly seen now that several of them were swarming about the Marsobus—that they were on much shorter necks, being almost a continuation of the body itself—and naturally giving a most peculiar dwarf-like appearance; and, moreover, the ears, set well forward and somewhat lower than normally, seemed to have another function.

"Gills!—that's what they are!" exclaimed Mackenzie at last. "Those fellows are fishmen. Never thought I'd live to see mermen!"

"Nor I," said Teddy. "And—and—look at their feet and hands! They're webbed! If—What's that for, Ashby?" he demanded, as the man shut off the searchlight.

"And the Chief?" Mackenzie asked quietly. "I'm not moving this bus until I feel it's utterly useless to stay."

"And isn't it so now?" Ashby demanded. "Even if he's anywhere about, those horrible people—fish or men, I don't know what—will get him, and—"

"You'd leave him to them?" Mackenzie asked. "Why, man, that's all the more reason why we should stay!"

He stopped abruptly as the intense darkness outside suddenly changed to light; and when the three men looked out once more, they saw lights, scores of them, flashing upon the water; and Teddy Craig, remembering experiments in far-off school days, cried:

But, attention was diverted from the lights to the men in the water; scores of them were crashing their knobbed staves on the Marsobus, without, of course, doing the least damage.

"They can use those things as long as they like," Mackenzie said, "and we shan't mind."

"That's all very well, Mac," Teddy suggested, "but we can't stay here indefinitely and do nothing. What's the next move for us?"

"There's Appleton to find, if he is to be found," was all that Mackenzie said, and that was enough for Craig, who was content to do anything in the hope of finding the Professor—remote us that possibility seemed.

So the Marsobus, rolling slightly to the lap of the water, remained where she was and allowed the strange denizens of the underworld sea to batter away at her hull without anyone interfering with them, for Mackenzie had decided that violence might have very undesirable effects later on if necessity arose for any move outside. And all the time that the attempts were being made to force an entrance into the machine, both by means of the knobbed and spiked clubs wielded from the water, and also by means of the same implements in the hands of men who, clambering up on to stalagmites, dropped on to the top of the Marsobus and sought to find a way in there, the adventurers peered through their windows and, between the whiles of watching the futile efforts of their assailants, kept open eyes for any sign of Appleton, on whom all their hopes rested.

CHAPTER 7
Appleton in the Hands of the "Gill-Men"

WHEN Teddy Craig gave him the thrust forward that sent him staggering out of the range of the dropping sword, Appleton hadn't the least idea of the meaning of it, or the reason for it, and during the next few minutes he had little enough opportunity to think about it, because when he slumped into the water, spread-eagle fashion, instead of floundering on to the bottom, there was no bottom. He was snatched, as it were, by unseen and unfelt hands, and knew that he was dropping through space as black as the pit itself. The sensation of falling was brief, but the sensation of impact was briefer, for he was rendered unconscious, though fortunately, as he discovered when after a while he regained consciousness, he had no bones broken.

On opening his eyes he was blinded by a glare of light, which prevented him from taking in the scene for a time. But when he was able to do so, Appleton found himself gazing upon a great company of people similar in every respect to those who, had he but known it, were even then making their attack upon the Marsobus. He himself was lying on a kind of platform—and he was to learn later that while he remained there the sword of the stalagmite statue was down and the water rushing from the concealed reservoir. He stared at the figures ranged around the cave-like place in which he was, all of them gazing at him in seeming wonder, but none of them speaking a word. Appleton tried to rise, but found that he was secured to the platform, and a sidelong glance towards his outstretched arms showed him that his wrists were held to the platform by iron rings.

"Somewhat of a mess," he said to himself grimly. But he had little time for further thought, because several of the onlookers advanced towards him, and a moment or so later he was released from the rings and lifted off the platform. He heard a sharp click and, glancing quickly behind him, saw that the platform sprang upward several feet. Instantly there came the recollection of what had happened—the push given him by Craig and the sudden terrified cry of the youngster—and he connected the platform with the statue, though how they operated he could not imagine.

Immediately the platform had risen there was considerable bustle on the part of the strange-looking people. Some of them hurried Appleton along a tunnel, others snatched up clubs and followed the leaders. The captive made no resistance. He knew it was useless to do so and that his best course was to wait and see what happened.

Appleton, walking between two of the strange people, with arms now unbound, impulsively did what calm thought would have told him was useless in the circumstances. Furtively his hand sought the waterproof case and drew out his automatic. Then with a bound he was at the rock, facing his captors, who, taken by surprise for the moment, recovered quickly and made a rush at him. Appleton, still befuddled of brain, fired, but his unsteady hand rendered his aim faulty, and he missed a body—but his shot smashed one of the lights placed in the wall opposite.

The effect of that silent shot was remarkable. The captors fell away from Appleton and disappeared as if by magic, while a second or so later the tunnel was in darkness.

It had been illuminated, as Appleton was interested to notice, by lights set in transparent shells filled with a clear liquid—he was to learn that these were potassium lamps, and that they were extinguished by withdrawing the water. What was the object of plunging the tunnel into darkness Appleton did not for the moment realize, his hazy mind playing him queer tricks. But he was soon to know, for, even while he was groping for the electric torch, he was suddenly seized—and, although he struggled violently, he could not bring his weapon to bear. It was, indeed, knocked out of his hand, and he himself was bound tightly, hand and foot. And when the lights came on again, as suddenly as they had gone out, he found himself surrounded by scores of the gill-folk—Gillies, he had already facetiously dubbed them. He saw that one of them had his automatic and was examining it curiously, and Appleton had a sense of dread that the man might unknowingly fire it. Appleton shouted, and the man started. Appleton shook his head vigorously and looked up at the smashed lamp, and his meaning was obviously understood, for the man actually held the weapon against one of his comrades and, evidently having noticed what Appleton had done, deliberately pressed the trigger, and the unfortunate wretch screamed with pain as the bullet got him.

Again Appleton shouted, and the only result was that the man bared his teeth in a cruel smile. And Appleton trembled at the very thought that this fellow should possess the power he did possess in having the weapon. The Professor could, however, have sobbed with relief when, as if to test the thing again, the man pressed the trigger—and nothing happened.

Again the man tried, but without effect; and Appleton, relieved now, laughed aloud. The man slashed at him with the handle end of his club and Appleton promised himself to exact full value for the blow at some time if opportunity presented itself.

For the moment, however, he could do nothing except, when the bonds about his ankles were loosened, march along the tunnel, with some of his captors going before him and others trailing behind.

CHAPTER 8
War in the Great Cavern

IT was a very stiff climb along the tunnel, although the floor was smooth, as though it had felt the tread of multitudes of feet. Walking with a man holding each arm, Appleton examined them curiously, struck by the webbed hands and feet and the peculiar formation of the ears.

Also, despite the fact that he was still hazed, he had enough wits left to make him look for signs of weapons other than the knobbed clubs, but he could see none, and somehow that gave him a sense of relief. Dully he wondered whither he was being taken, and whether he would again see the Marsobus and his comrades, who must be somewhere above, since he had dropped. And the fact that he was now going upward gave him hope.

It was, however, hope long deferred, or so it seemed to Appleton, for when at last the crowd of strange people came to a halt he found himself, not looking out upon the underground river, but in a cave which reminded him only too much of that in which he had so nearly escaped death by "grilling." He was led to a building cut out of the limestone rock, bound hand and foot, and left alone in the darkness to exercise his mind as to what fate was being prepared for him and what had happened to his comrades. How long ago it was since he had fallen through the dark space he did not know. All he knew that mattered was that he was a captive to a people who regarded him as something very strange, and, since they took precautions to bind him, as either a danger or as one whom they desired to keep for some purpose of their very own.

If Appleton had only known, there were even now some of his captors hurrying down the channel that led to the menacing statue, swimming at an amazing rate of speed. Their object was to see what had happened before the arrival of their strange guest, and to find out whether he had any companions. For, as Appleton was to discover later on, the statue standing by the side of the river was a sentinel for the people who lived beneath the world. So far from Appleton's theory being correct—namely, that the presence of water in the channel precluded any likelihood of the statue being worked mechanically, as its first appearance suggested—it was so arranged that, as it was impossible for anyone to swim in the shallow water, any attempt to wade past the idol would have the result of setting the mechanism in motion; and first, whoever did that would be precipitated through a trap, which closed immediately afterward; and secondly, there was released what seemed a solid wall of rock behind which percolated waters were pent up, only to be freed in a mighty rush when the wall slid open—with what result we have seen already.

The necessity for such precautions was to be realized by Appleton very shortly; as a matter of fact, the people with whom he now found himself were deadly enemies to another tribe of troglodites, and their underworld city was protected from attack only by the menacing idol. The channel beyond was the only way into their city that was known to their foes, and, since past experience had been bitter and expensive of late, their enemies had for many years made no attempt to attack. For this reason the captors of Appleton had been considerably amazed when they received, by arrangements specially devised for that purpose, indications of the interference with their protective idol. Hastening to the cave, they had seen the unconscious form of the stranger—a form so unlike their own or any they had ever before seen. They had expected to see one of their traditional foes; instead, they saw this—and a fear consumed them that some people of whom they had hitherto been in ignorance had discovered their existence. Therefore they secured their prisoner, who came back to consciousness within a very few minutes, and then they hurried him into their city, there to await the report of spies sent out to see what was afoot.

Those spies swam until they came to the point where swimming was impossible owing to the shallowness of the water, and then, diving, they entered a water-filled cave through which, by virtue of their gills, they were able to swim and so come out into the broader stretch of deep water, where the Marsobus was just mooring after returning from her fruitless search for Appleton.

If Appleton had been amazed to see his strange captors, and if they had been astonished at first sight of him, these emissaries of the troglodites were overwhelmingly surprised to see this tremendous thing which was like nothing with which they were familiar; and the sight of the three men on her, similar to the one who was held prisoner away back in their city, caused them no little anxiety.

They had, however, little time to ponder over this mysterious thing, for even while, from afar, they looked upon it they saw, coming down the right hand channel, the swarm of swimmers who had so startled the adventurers and sent them scuttling back into the Marsobus.

They recognized them instantly as foes, and, curious to know what would happen, they remained in the shelter of some stalagmites. Their first impression was that their enemies were in league with these strangers, and bent upon an attack on the city beyond the idol. But when they saw the strangers disappear within their craft, and witnessed the futile attack upon the latter, they realized that whoever the strangers might be they were not unfriendly.

For a while they remained concealed—but seeing. And at last one of them was ordered back to the city to carry the news.

Arrived at the city he told his strange tale, and immediately a council was held, at which it was decided that there was presented a splendid opportunity to settle account with the enemy. Then some wise head suggested that the captive might even be pressed into service, since the use of that strange weapon of his, which destroyed without noise and so mysteriously, might prove an effective agency. The problem was how to make him understand this. And the "Gillies," who were by no means wanting in mental capacity, decided that the best way to do this was to get him to the scene of operations.

Appleton, who had been left in the dark room where he had been placed some time before, was fetched out. A large number of the "Gillies" then dived into the water which ran through their city, and Appleton was not a little interested to notice how long they could remain under water. He himself was forced to march on the solid rock beside the water, and he found it was difficult to keep up with the swimmers. He judged that he had walked something over half a mile when he reached a solid wall of rock—and yet none of those who had taken to the water came to the surface. During the few moments that he remained there Appleton, whose senses were beginning to revive, came to the conclusion that the swimmers must have found an outlet from the river; and, naturally, he put the fact down to the account of the gills that these creatures possessed. As a scientist he was less disposed to wonder at the phenomenon than were the comrades whom he had left, he knew not how long or short a time since; he argued from the end that circumstances, which are more often scientifically called environment, had produced a race of people whose continuance depended upon being able to exist in water; and his scientific knowledge taught him that there was nothing to be amazed at, since even on the Earth to which he himself belonged, there were such beings as amphibians. Therefore, the fact that these strange folk could remain under water for a long time was no wonderful phenomenon. It was as natural to the world to which they belonged as walking on solid ground was to the people of Earth; the process of evolution had ordered it so.

What was passing through Appleton's mind at that moment was that he would have liked nothing more than to be able to don his diving helmet and show these captors of his that, up to a point, he was as capable as they were of remaining under water. But, failing that, the Professor decided that his best scheme was to do exactly as possible what was demanded; and, although he did not for a time know what was being arranged, he very soon obtained some sort of impression, and came to the conclusion that he was required to take a plunge into the water, several of the captors actually doing it as if to make him understand. Appleton realized that undoubtedly these people imagined that he was able to do what they could, but he himself was by no means sure on that point. He tried to make them understand, but they wouldn't, and, having unfastened the bonds about his wrists, they would actually have thrust him into the water had he not sprung aside and whipped out his second automatic—at which they looked terribly afraid and drew away. Appleton's brain, clear now, was working rapidly; he had pieced together the various little things which had happened, and he came to the conclusion that the likelihood was that beyond that seeming solid wall of rock lay the Marsobus, although how to get to it was his greatest problem; he certainly dared not risk diving into the water and trying to emulate these folk whose physical formation enabled them to remain under water as if they were fishes. Nevertheless, the ingenuity born of necessity suddenly gave Appleton an idea. He thrust one hand into his pocket—there was a scatter of the "Gillies" as though they expected him to pull out another of those terrible little weapons; but, instead of that, he drew out a pocket book. Holding his automatic in his left hand, and so keeping his enemies at bay, Appleton proceeded to draw upon a sheet of paper a rough picture of the Marsobus: it had occurred to him that people who could erect a statue such as he had seen outside, certainly ought to be able to understand a pictorial representation. This deduction proved to be correct, inasmuch as immediately he threw the sheet of paper towards one of the men, who picked it up and looked at it, it was taken to another man—the fellow who had come with the news of the presence of the strange thing beyond. Instantly there was a clatter and a clutter of excited talking.

Appleton knew at once that he had succeeded so far; and his next step was to get a message to the Marsobus. He made signs of inquiry, which resulted in his believing that the Marsobus lay beyond the wall; and then, taking the drawing again, he scribbled a message on it:

"Mac. If this reaches you, follow the guide. Wear your diving helmet and bring mine, because I reckon it's a case of travelling under water.—Appleton."

Then he gave back the paper, pointed to the figure of a man that he had drawn on the Marsobus, and by frantic motionings succeeded in conveying the impression that he wanted the man brought to him. Appleton, naturally, did not know that the Marsobus was being attacked by another tribe of these aquatic people, and when he saw one of his captors screw up the scrap of paper and dive into the water with it, he felt that he was as good as rescued. He did not realize how difficult a task he had set that man, or how amazed Mackenzie was to be, when—while peering through the window of the Marsobus, watching their assailants in deep consultation, having withdrawn from the attack for the moment—he suddenly saw a man swimming beneath the water and come up to the surface just beneath the window where he stood, and wave a piece of paper.

"Come here, Craig!" yelled Mackenzie, the moment he saw it. And Craig, who had been at the opposite window watching a consultation amongst their assailants who had just drawn off, rushed over to the engineer. "There's a fellow with what looks like a paper, and he's waving it to us. What the deuce can it mean?"

"Then why didn't he come from that bunch of folk on t'other side?" Mackenzie demanded. "And hullo, he's coming nearer; man, don't you see that it's downright rot to talk about a peace herald bringing us a written message? Those people would jolly well know that we couldn't understand anything they might write."

"Well?" Craig asked, quietly; but Mackenzie knew that the youngster was thinking just as he was.

"It can mean only one thing," the engineer said; "Appleton is alive and somehow has managed to send a message to us. But what I can't understand is, that while those fellows attacked us, this chap seems to be trying to remain concealed from them." This was the case, for instead of remaining on the surface all the time, the messenger kept sinking and coming up again, and always he remained in the shelter of the shadow thrown by the Marsobus. "Anyway, we'll have to risk things. I'm going to—"

"Open the top door?" Craig asked. "I shouldn't; I'd suggest that it would be best to slide aside the cover of one of the gun ports and thrust out a hand to take the paper. If it should happen to be a ruse to get the better of us, we'd be safer. What do you think?"

"I think you're right, Teddy," Mackenzie agreed, and proceeded to do what Craig suggested, Teddy—and Ashby, who had been told what was taking place—meanwhile keeping a watch upon the band of foes on the other side, in case there should be any signs of attack; not that attack mattered much, after all, but it would at least show whether there was any connexion between the messenger and the assailants. Actually, nothing of that kind happened, and Mackenzie's groping hand, thrust through the narrow opening in the side, showed white in the light-glare. The messenger, seeing it, swam towards it and held up the paper that he had carried; Mackenzie felt it, and clutching it in a hand that shook a little, slid back the cover of the port, and cried, as his eyes fell upon the writing:

They crowded over that slip of paper and read the words which meant so much to them; words which meant that, after all, their Chief was not dead, even if he were a prisoner; words which might also mean that, after all, they would not be condemned to remain on that mysterious planet.

"Do?" the engineer almost yelled at him. "Do? Why, I'm going to do as the Chief asks, you bet! Hurry—give me the helmets quickly!"

Feverishly they worked now, and Mackenzie was presently wearing his helmet, and had Appleton's strapped upon his back, while outside Craig could see the messenger lurking just beneath the surface, waiting.

"Ay," Mackenzie told him as he gripped a knife, ready for emergencies, in case, after all, there should be any attempt on him when he was in the water. Then he entered the diving box, and a moment or so later was to be seen in the water with the messenger speeding away from him as if in terror.

"That looks pretty bad, Ashby," Teddy said. "If that fellow's so scared, he'll not be much of a guide for Mackenzie."

"Confound it all, and everything!" rapped Ashby. "I'm fed up with the whole show, and don't care what happens. We're only getting what we asked for when we started on this fool business; and I—I who didn't want to come, am getting it too."

There was a mad light in the man's eyes, and Teddy shuddered at the prospect of being cooped up with him, if, as might easily happen, things went wrong again.

"Come. Ashby, old chap," he said soothingly. "Let's hang together. We'll soon be out of the mess, and—"

"Into another one!" growled Ashby; and then became silent and remained so for the rest of the time, until the moment when even his moroseness was broken by a sight that cheered the heart of Teddy Craig.

Meanwhile, Mackenzie was waiting beneath the water for the return of the stranger who had fled at his appearance; and he had not long to wait, for the messenger suddenly stopped in his mad rush and looked behind him, stared at Mackenzie for a while, and then swam back a little way, beckoned to Mackenzie, and dropped beneath the surface. Mackenzie, who had been holding himself up by the Marsobus, followed him, gratified to see that he was going away from the spot where the erstwhile attackers of the Marsobus were in council; and, walking on the bed of the water, Mackenzie at last found himself plunged into darkness. Previously there had been light reflected through the water as the result of the chemically produced brilliancy on the surface; but now it seemed to be blotted out, and Mackenzie's idea was that he had entered a tunnel of some kind, since, looking behind him, he could see the shimmer of light. Then, to his surprise, there appeared a tiny gleam before him—a gleam that moved away, and although he did not understand how it was produced, he came to the conclusion that his guide had a light. Mackenzie followed the gleam, and as he did so he switched on the electric lamp in his diving helmet. The stream of light showed him the figure of the guide, and the man was blinking as the ray fell upon him. Only for a moment or two did the man remain thus—and then he was going again, walking, as Mackenzie himself was, on the floor of what the engineer saw really was a great tunnel. It ended abruptly, and Mackenzie wondered: "What next?"

He knew very soon, for he saw his guide press upon the rock face, saw a great slab swing forward and the water rushed into what had before been a dry, cell-like place.

"A lock, of a sort," Mackenzie breathed, as he followed the man, who passed through the opening; and immediately after wards the door closed.

Mackenzie found himself in a water-filled compartment, and his light showed him his guide working another door on the farther side. It opened, and the guide went through, followed again by Mackenzie, who found that beyond the tunnel was wholly filled with water as before, and Mackenzie waded in the wake of the leader until he saw him suddenly rise—and Mackenzie, loath to lose the heavy diving boots which kept him on the floor, had taken a coil of string that he carried in his pocket, and then, removing the foot-gear, he rose up through the water, trailing his line behind him. He found himself not on the surface even yet, but could see the figure of the guide striking for an arch. Mackenzie began to swim now—and he too, entered the arch—to find himself at last rising, until he was on the surface; and seeing through the water-streaming glass of his helmet the form of Appleton standing on the side of the river, whence he had sent the message that had brought Mackenzie on his strange journey of succour.

As for Appleton, the appearance of his comrade sent a thrill of pleasure and relief surging through him; and he told himself that everything would be all right now. He watched Mackenzie make for the bank, and he himself helped the engineer to land; helped him, too, to remove the helmet.

"Mac!" was all that Appleton said; and the engineer, gripping his hand, exclaimed: "Chief—thank Heaven I've found you. Now, what about things?"

"No time to tell you all, Mac," the Professor said. "I've been a prisoner—and am now, I rather fancy, although one who can move about rather freely."

"Yes, Chief, we managed to get him," Mackenzie told him, as, having unstrapped the helmet that he had brought for Appleton, he fished up the two pairs of boots. "Explain, if you can, this: There's a bunch of these fellows attacking the bus, and yet the man who came with your note did so secretly, and didn't show himself to them."

"Ask me another," said Appleton. "We'll find out presently, because these people, as far as I can make out, want me to go with them to the place beyond here. Help me on with the helmet, and then put on your own."

He had by now put on the diving boots, and in a few moments the pair of them were standing facing the evidently astonished people, who seemed to be waiting to see what these men were going to do.

Appleton had succeeded in getting the information from Mackenzie as to the nature of the route into this place, and, ready to go, he made signs to the "Gillies" to that effect. They were quick to understand—and scores of them immediately dived into the water, each carrying on the top of his bludgeon a tiny lamp, fashioned, as Appleton had seen during the time of waiting, out of two transparent shells—fastened together and carrying water and a spot of potassium.

"In!" Appleton said through the visor in the helmet that allowed speech, and he and Mackenzie promptly followed the Gillies into the water, their own head-lights showing them the figures of their strangely found companions.

The journey into the great watercourse where the Marsobus lay was made in rapid time, and following the example of their leaders, the two adventurers shut off their lights as they did so—wondering at the meaning for it, but quite prepared to wait for the reason to show itself.

Releasing themselves of their boots, the divers went to the surface, and saw the Marsobus being attacked by a swarm of the little folk.

To their amazement, however, there were bunches of the people who seemed to be fighting among themselves; in the water, on the rock-sides, everywhere, in fact, except at the Marsobus, where the crowd was concentrating its efforts in trying to force an entrance.

Appleton, who had removed his helmet by now and drawn up his boots, suddenly grasped the significance of it all.

"Mac!" he said, "these are two sets of people—foes! And they're fighting it out. And our crush wants us to help 'em!"

"How the deuce are we to know one from t'other?" the engineer asked. "They're as like as peas and—"

Actually Mackenzie had not noticed before that the people whom Appleton called "their crush" had hair upon their heads, whilst the others who were attacking the Marsobus were bald.

A band of the former were around the adventurers, and the man who had appeared to be their leader was gesticulating, waving the empty automatic towards the bald men, as if urging Appleton to use it against their enemies.

"What about it, Mac? They want us to fight for 'em!" the Professor said. "Shall we?"

"Guess, mon, those other fellows are no friends of yours!" was the reply of the Scotsman as he produced his own weapon. "I'm wi' ye!"

They had placed their diving gear behind a stalagmite, and they themselves took up a position near it. Appleton it was who fired the first shot at a man who, banging away at the top of the Marsobus, sprawled down on the instant with a loud cry that was heard above the multifarious noises going on; and the man who was beneath him ceased his own attacking and gazed in wonder at him. Next instant something that he could not see struck the club from his own hand.

CHAPTER 9
Secrets of the "Gill-Folks'" City

THE man sprang off the Marsobus at once; he had caught sight of Appleton taking aim at him and had at once connected the mysterious happenings with him. By this time others of the attackers had realized that there was something strange afoot—especially as the moment they saw Appleton and Mackenzie firing, both Ashby and Craig decided that they might do so, for it was clear to them that Appleton had made friends with people who were by no means friendly with the assailants.

And so that strange fighting went on, deadly execution being done by the heavy clubs, and yet the overwhelming numbers of the attackers bade fair to give them victory, despite the assistance of the adventurers to the other side. Moreover, after the first shock of the experience of those mysterious weapons, the enemy seemed to lose their fear of them, and more than once crowds of them swarmed towards Mackenzie and Appleton, only to be forced back before streaming shots. A club whizzed through the air and struck Mackenzie a terrific blow on the forehead. The man went sagging down and tumbled into the water, unconscious. Appleton salved the automatic that dropped to the rock, and then, thrusting his own and Mackenzie's into the waterproof cover, jumped in to the rescue, with the knowledge that he was in for a stiff time. He grabbed the engineer and supported him, waved with one hand towards Craig, who was peering through the window, and the youngster, realizing his intention, sprang to work at once.

"Drive the bus along to 'em, Ashby!" the youngster cried; and the other, alert and forgetting his grouse now that action was required, obeyed; while Teddy was up at the top trap, ready with the rope ladder, and he knew that he would have to take the risk of some of the attackers, still on the machine, getting in.

Meanwhile Appleton had managed to drag Mackenzie to the bank again, and hauled him up—having knocked out one attacker with a fist, that thumped heavily upon the broad face, and, seizing the man's club, had, thanks to longer reach giving him advantage, succeeded in keeping off several others who attacked him, while some of the friendly natives, seeing his plight, left their own affairs and raced to his assistance.

Safe on the bank again, Mackenzie was placed behind one of the stalagmites, ready to be put aboard the Marsobus on its approach, and Appleton stood guard over him.

The Marsobus came at last, and Teddy Craig slid open the door on top; a man dropped through and was promptly handled by Ashby, who was below ready for such an emergency. Next instant Craig was outside, and the rope ladder was flung down to Appleton.

Mackenzie had recovered consciousness, but he was still dazed, and when Appleton helped him to the ladder, the engineer only managed to haul himself up with great difficulty. Appleton steadying the ladder while he did so.

Quick to see their opportunity, the enemy, scrambling like monkeys among the stalagmites and stalactites towering above the Marsobus, dropped on to the machine, and Craig and Ashby had the times of their lives in battling with them. Small though the foe-men were, they were strong, and, moreover, as soon as any were flung off after a struggle, others took their places; and there were many more, leaving for the time being their traditional enemies, who were rushing to the attack. Even with their automatics, it looked as though there were nothing but defeat awaiting the adventurers; but, help came to them in a dramatic manner from a totally unexpected quarter.

Down in the Marsobus the native whom Ashby had made a captive, and who had become quite friendly since he found that no harm was intended against him, had seen the fight; he realized what straits his captors and friends were in, and quick-witted as he was, he saw a chance to help. He had seen Appleton put in the locker the ball-shaped object that had been found on the floor of the Marsobus, the use of which was unknown to the adventurers. But he knew—and he extracted it from the receptacle, bounded up the steps to the top of the Marsobus, and Teddy Craig, at that moment locked in a hand to hand struggle with two of the enemy, caught a glimpse of him as he stood poised there with the ball in his right hand.

Then the man's arm swung out, the thing that he held was loosed, and a second or so later the whole cavern was filled with a roar of sound and a suffocating vapour. There was an uprush of water like a geyser, and the Marsobus itself rocked to the swell set up. The enemy with whom Craig had been wrestling yelled aloud and leapt away, and Teddy, greatly wondering, stared over in the direction whither that globe had been hurled, and saw rising clouds of vapour hiding the crowd of foes which had been rushing to the attack of the Marsobus.

Those of the enemy who had been near the machine were evidently alarmed, not to say scared, for they began to swim away, pursued by the allies of the adventurers who, quick to seize an opportunity made by means that they did not understand, were bent upon completing the discomfiture of the foe.

"Come up, Chief!" Craig shouted down to Appleton, who had found himself freed of his attackers; and the Professor sprang up the ladder on the instant, and shook hands with the black, who, by this time, had some glimmering of the meaning of the act, and looked very pleased with himself.

"It's a good job we let that fellow go free amongst us," the Professor said; "he saved the day for us, undoubtedly. And that bomb of his was a mighty powerful thing. My goodness—see what it's done!" He pointed a shaking finger towards the spot where the bomb had dropped; there, floating on the surface, were scores of mangled enemies.

"It's horrible, Chief!" Craig breathed; "but it's saved us." He dropped down the ladder as he spoke, and Appleton needed no telling to understand what he was going for; he was fetching up the two diving helmets and the boots which Mackenzie had taken from the Marsobus.

When he got back to the machine he found Appleton tending the bruised head of Mackenzie, who grinned sheepishly as he said:

"Fainted like a girl, laddie. But, faith, those wee men have a punch like a coo's kick!"

Despite the tension of the last few hours, it was impossible not to laugh at the man's manner; but the mirth was short-lived, because at that moment there came the sound of a scuffle on top of the Marsobus, and Craig, rushing up, was just in time to see their captive go tumbling into the water, hurled overboard by a couple of the small men who, evidently, had jumped on him from overhead.

He was unarmed, and, despite his larger build, and the fact that he, too, could swim like a fish, the man had little chance against his enemies, who possessed their formidable clubs and were beating him severely, as he tried to swim round to the side of the machine down which the ladder was still hanging.

Craig knew that he must do something, and he fired at the man who was further away from the black; he did not dare to fire at the other, who was too close to the victim for safety. Craig's bullet went home, and the aquatic creature sank. Meanwhile the black had turned on his pursuer, and, making a quick dive just as the club descended, came up behind his enemy—and his hands were about the short neck. Then began a terrific struggle in the water—a struggle in which Teddy could not interfere for fear of busting his own ally; but he had little need to, really, since the black, now that he was at grips, proved to be the stronger man, and after a while the aquatic foe was gone to keep company with those scores of his companions who had finished their course during the strange battle.

Immediately his fight was over, the black scrambled up the ladder and, emulating the example of Appleton such a little while before, he grasped the hand of the youngster and made the weird guttural sound that the adventurers had learned to understand as being an expression of thanks: he had known how it was that there had been only one enemy left for him to deal with.

It was when he was about to descend into the Marsobus that something happened—something that caused Craig to gasp with astonishment and alarm. The roof of the cavern suddenly bulged and gave way with a thunderous crash about the Marsobus and the channel farther down.

"My word!" he cried; "we're trapped in here," and he shouted down to Appleton to come up. "Look, Chief!" he cried, pointing to what he had seen. "That explosion has brought down a whole heap of rock, and it's filled up the way out!"

It took but a glance to tell Appleton that Craig was right; a great fall of rock was lying across the narrow bottle-neck of river up which they had passed when they came within sight of the guardian statue. They had not seen it when they looked that way before, because the vapour-cloud was not all cleared away and hid from view anything beyond.

"That's serious," said Appleton solemnly, "It's pretty obvious what happened. That bomb struck one of those great stalactites that reached from the top to the bottom, and smashed it, bringing down part of the roof with it. Come on, let's get out the boat and go to see exactly what it means for us before those 'Gillies,' come back from their chase. Bring my helmet, too."

Except for the dead and the wounded, all the natives had gone in pursuit of their foes, and so the adventurers found that they could prosecute their investigation without interruption for the time being. Mackenzie and Ashby remained on the Marsobus while Appleton and Craig went across to the rock in their collapsible boat. It did not take them long to come to the conclusion that the tremendous fall of rock was going to be a serious obstacle for them to remove before they could go back the way they had come. A descent into the water by Appleton showed him that there was no hope of the Marsobus passing beneath the rock, and, since, as far as Appleton knew, there was no other way out, the labour was inevitable. Moreover, unless he could prevail upon the friends he had so unwittingly made to remain with them while the work was in progress, the toilers would be exposed to attack from the survivors of the tribe of aquatics that had just assailed them.

"It's a case of hard work for us," he told Craig. "But we're not starting it now—I'm dead tired, and I reckon the rest of you are. We'll wait, until the Gill-folk come and then see what happens. Let's go."

So back to the Marsobus they went; and, during the time that they were waiting the coming of the Gill-folk, the tales were told of what had happened to lead up to the present situation.

"I had hoped," Appleton said, when the yarns were ended, "to pay a visit to the Gill-folk's city and make an examination of it. But we'll have to see about removing that obstacle first, and I'm not over-anxious to extend our stay here. But we'll think about it later and—" Shouts outside the Marsobus interrupted him, and the adventurers went to see what was happening. They found that the Gill-folk had returned, and from their manner they had had what was to them an entirely satisfactory expedition. The Chief stood on the bank and made an impassioned speech, not a word of which, naturally, was understood by the adventurers, who, however, took it for a complimentary ovation; there was, indeed, no mistaking that that was the intention. When he had finished, the Chief swam up to where the statue stood, with its menacing sword out-stretched, and waved a hand of invitation.

"Wants us to go with him to his city, I suppose," Appleton said. "But if that's the way, I'm not for it! Besides, I'm not anxious to leave the bus here—those other fellows may take it into their heads to come back, and it may be a bit difficult for us to get into the machine if there's a crowd of 'em. They can't damage the machine, I know that, but—"

"Look here, Chief," Mackenzie put in, "if that chap invites you to his show, it's a cert that he won't enter the way you did first; he'll take you the way I came, or else there's some other way. I know you'd like to go, and I'm prepared to stay with the machine."

"So am I," said Ashby sullenly. "I'm fed up, anyway, and I'm not going to poke my head into any more trouble."

"All right, Ashby," Appleton told him, with a soft laugh; he had come to the conclusion that thy best way to deal with the discontented comrade was not to take him too seriously, anything in the nature of opposition causing the man to flare up into a great temper. "If I can make these people understand about the rock, I may be able to get them to help us; they must have tools of some kind, because they've got dwellings out in the solid rock. Hullo—what's happening?"

It did not lake more than a moment or so to understand what had happened; several of the Gill-folk had swum up to the fall of rock and had shouted out to their Chief, who went to them immediately. The little bunch of people began to gesticulate and to speak together, pointing to the Marsobus as they did so; and Appleton, quick to seize the chance that had presented itself, said:

"Out with the boat again, and load up the pickaxes! I think I can make them understand!"

Within a few moments the adventurers were rowing across to the rook, and immediately on arrival disembarked on to a separate piece that lay in the water close at hand. "Fall to," Appleton ordered, and the four of them began to hew away at the rock. Only for a moment or two did Appleton toil thus; then he stopped and began to try to indicate to the Chief of the Gill-folk that he wanted the great rock removed. The chunks of the rock smashed into the water beneath the blows of the picks as Appleton pointed from the Marsobus to the rock; and the Chief quickly seemed to understand what was intended. He shouted out something to his followers, many of whom went swimming off, and, to the surprise of the adventurers, went straight past the statue, wading through the shallow water beyond it.

"Fall to," Appleton ordered, and the
four of them began to hew away at the rock.

"Ask me another," said Appleton. "But it seems obvious that these people can put that mechanism out of working order when they want to. That explains why the Chief's invitation was for us to go that way instead of the way that Mackenzie went. Anyway, they're meaning to do something for us, I should think. We'll see in a little while."

Meantime the Chief was making signs which Appleton interpreted to mean that the obstacle should be removed, and then, seeing the black man standing on the top of the Marsobus, he raised a shout; those of his own people who were on the bank prostrated themselves.

"Giving-thanks, I guess," said Mackenzie. "Anyway, we all seem to have won the friendship of these fellows, which is so much to the good. We'd be in a nasty mess otherwise, with that fall fronting us!"

"That beggar," was the black; he was standing, a fine-looking figure of a man, despite his ugliness of face, with pleasure writ large on his features, and he was accepting almost royally the obeisance being offered him.

"If he only knew how jolly near he has come to bottling us all up in this place," said Ashby, growling, "he'd kick himself. I'll wring his neck myself if we can't get out, so there!"

A few minutes later there came floating down the narrow channel beyond the statue a raft, on which were numbers of the Gill-folk, together with a crane, and the adventurers, who had given up being surprised at anything, knew that their present difficulty was removed. They watched the little people manipulate their machine and raise some of the obstruction, weighing many tons, as easily as if it were only a few pounds in weight.

"How's it worked, I wonder?" Craig asked Appleton, who had been examining the crane and noticed that it was connected with a tube that stretched away up the farther channel.

"Don't know yet, but we'll find out when we go with our friend, the Chief," the Professor said. "Mac," he went on, "are you and Ashby still willing to stay here with the bus? Right; then Craig and I will go."

He made his intention known to the Chief, and a little later he and Craig accompanied the band of troglodytes up the channel beyond the statue. As Appleton had surmised, it led them by a direct route straight into the city that he had left not long before.

Keen as he was on exploring the city, Appleton, tired out, elected to sleep first; and it was not until several hours later that he began the work that gave him one of the most remarkable chapters in that amazing book which records the story of his journeys and discoveries. The city was really a system of underground caves, with dwellings hewn out of the rock. Everywhere there was evidence of a high degree of intelligence, and Appleton discovered that the Gill-folk had a most elaborate system of water-power, by which they operated their various mechanical labour-saving devices; the crane that had removed the rock had been worked, as he found out, by a kind of wave-transmission. There were water-wheels that operated fans that circulated throughout the various tunnels and caves the air that entered by way of shafts cut up to the glacial country above. The Gill-folk lived chiefly upon fish, and various marine vegetables of a kind unlike any with which Appleton was familiar.

The homes, as well as the persons, of these strange people were decorated with gold and precious stones, and Appleton saw the source of these treasures.

"Teddy," he said, "we can see here the process of world-making, and it is fairly evident that ages ago this planet was overwhelmed by a great catastrophe, and its people forced to adapt themselves to the new environment. Here, the people were driven underground because the ice fields would not support life. On that other small continent we visited they chose to live on ships because there was not room for them on the land. What other things we may discover there is no telling, but I am determined to make a further exploration."

"If Ashby will let you," Teddy said with a grin. "I'm not sure that you did well, really, to leave him with the bus. Suppose he took it into his head to go>! He might do anything these days!"

"No need to worry about that, anyway," Appleton told him. "Ashby knows that he can't leave without me. That fact, by the way, is a serious one, that I must put right as soon as we get back, to the upper world; it's not right that you should all have to depend on me—all sorts of things might happen. So I propose to go back to the bus and make our way into the sea again, and then work out the trajectory, if I can, and put it on paper, so that any of you can read it if anything happens to me."

"Thanks, Chief," Teddy said quietly; he was thinking of the fright that he and the three others had had when they thought that Appleton was lost to them.

There were, however, several things to happen before Appleton had the opportunity to keep his promise. When he and Craig, attended by the Chief of the aquatic people, were finishing the tour of inspection, Appleton came upon the most remarkable thing he had yet seen in all his travels, namely, a submerged forest. There were the trees—gigantic specimens, every one of them; and as he stood gazing upon it, the Professor said:

"Craig—there you see how nature works. Some day that forest will turn into coal, and by that time the people who dwell here will have been crushed out of existence. Can't you see what's happened?"

"Can't say I do see," Craig told him, with a look in his eyes that asked for information.

"Look above you, then," Appleton said, and the youngster stared up. "See, lad, that's what it is up there. I can read the story: these people have always been troglodytes, even before they were doomed to live below. When the great glacial slide happened, the hills in which they lived were smothered, and by some remarkable means the ice, instead of smashing down upon the forest in the valley, simply poised itself upon the two hills; and there, for undoubtedly thousands of years, perhaps millions, trees have been growing, absorbing what little light filtered through the tremendous layer of ice. And it's through that ice these people get their air. Most remarkable, indeed!"

"Sounds all right, and you ought to know," was all that Craig, could say, as Appleton, keen to obtain a photograph of what he considered an amazing natural phenomenon, fixed up his camera.

It was while he was doing this that out of the deep watercourse running through the forest there suddenly arose a long-necked object that reminded Appleton of a saurian monster, before which the Gill-folk, who were with the adventurers, turned and fled by—diving into the water and swimming for dear life. In the queer light given off by the potassium lamps the brute looked more terrifying than it might otherwise have done; and Craig felt the whole strength of him depart. For a moment or so he stood staring at the menacing beast, unable to flee, unable to draw his automatic; he was as one paralysed. It was Appleton's voice and Appleton's quick action that brought Craig back to sanity and movement.

"Shoot!" cried Appleton, firing as he spoke. The bullet, meant to kill, merely served to whip the monster into a fury; its ungainly body moved towards the two men, its long neck lashing from side to side. Teddy came into action: his automatic loosed a shot that struck the beast over one eye; and a second shot, fired at the same moment by Appleton, sped into the ugly mouth.

The brute's neck drooped over on the instant, and the heavy body slumped into the water with a mighty splash which drenched the two men.

"A beautiful specimen," was what Appleton said. "We'll have it yanked out and take a photograph of it if these fellows will only come back."

"They're coming. Chief," Teddy said. "They must have been watching us from somewhere."

The Gill-folk were swimming back, with shouts of evident pleasure, and when they arrived they simply fawned upon the adventurers, who eventually managed to make them understand they wanted the monster got out of the water; and when this was done Appleton fired some magnesium wire and snapped the trophy, and that photoglyph—reproduced in Professor Appleton's book, to which we have before referred—shows a wonderful picture of the way in which nature works, for it depicts that wonderful age-old forest and one of the age-old monsters that dwelt in it.

"Absolutely topping," was what Appleton said as he took down the camera. "And now I think it's time we went back to the old bus. What do you think, Teddy? Ready for it?"

CHAPTER 10
Where Is the Marsobus?

THE Earth-men were not to go yet; there was a grim half-hour before them ere they could make their departure from the spot where they had had the encounter with the saurian, whose body lay upon the ground, its blood flowing freely into the water.

As Appleton said afterwards, it was no doubt the smell of that blood that, brought the swarm of wild creatures rushing out of the forest; creatures that seemed neither bird nor beast, and yet both.

"Pterodactyl!" exclaimed Appleton, as the creatures leapt and flew by turns, and his scientific enthusiasm overleapt all considerations of personal safety as he slung his smaller camera from behind him and proceeded to take a snap of the approaching herd. Craig, however, was more concerned about other things, and he fired rapidly at the pterodactyl, bringing down several of them, while the Gill-folk, probably acquiring confidence from the way in which the strangers had dealt with the saurian, stood their ground, clubs in hand, as though waiting for the moment when the creatures might attack.

Attack they did, too; some of them fell upon the carcass of the saurian, and others flew and hopped for the body of men, in the forefront of whom were Craig and Appleton, the latter now ready for what he saw was going to be a stiff proposition.

Rapid firing brought down several of the creatures, well-swung clubs accounted for more; but the agile movements of the pterodactyl resulted in several of the Gill-folk being beaten to the ground.

"One of those fallen clubs, Teddy!" came Appleton's order, as he himself seized one. And so, battering at the brutes when they flapped near at hand, firing at others, the two fought hard and long, while the Gill-folk gave a good account of themselves—all the time retreating, until at last they were round a bend in the channel, and found themselves able to deal individually with the pterodactyl who followed them.

It was then that Craig thought the end had come for him; one of the creatures fell upon him, enveloping him in its strangely-winged arms; and Teddy screamed with the terror of it. He was quite helpless, and as his muffled cry died away, Appleton sprang to his assistance.

It was impossible to use his pistol, and he had to fall back upon the club he held. With this the Professor began to belay the pterodactyl, and the lashing of the brute's tail as the blows fell thick and fast told that some impression was being made. Appleton was aiming each time at the head, and the thud of the club sounded even above the snarling of the pterodactyl, which suddenly gave a terrific scream and rolled off its victim.

Instantly Appleton sprang and placed himself between Craig and the creature, and panted out between more heavy blows:

"Yes—Chief," came the reply, scarcely above a whisper, as Craig scrambled to his feet and stood, unsteadily, with a blood-reddened knife in his hand—the knife that, he scarcely knew how, he had managed to drive full into the pterodactyl, now lying dead, Appleton having put the finishing touches to the grim work.

"Then go down the channel out of the way," Appleton told Craig. "Go! I say," as Teddy shook his head. Craig obeyed, and knew that Appleton was right in insisting, because he was considerably shaken, his left wrist was sprained, and his head aching from the crack it had received when he fell to the ground with the pterodactyl on top of him; besides which, the grim terror of it all had played havoc with his nerves.

Nevertheless, he did not go any farther than would allow him to watch the fight that was still going on, as, one after another, the pterodactyl hopped or flew round the corner, to be tackled either by Appleton or some of the Gill-folk, until at last the end came as the survivors of the brutes, with almost human intelligence, ceased attacking and made their way back into the forest whence they had been lured by the blood of the saurian.

"Just terrible!" cried Appleton, when he reached Craig. "I'm through—I'm going back at once! Come on, Teddy, How d'you feel?"

"Rotten isn't the word for it," was the reply. "It's the worst half-hour I've known."

"The same here," said Appleton. "I'm beginning to sympathize with Ashby. Thank goodness he wasn't here—he'd have gone mad! Really, I think he must have had a premonition when he kicked up that fuss before; we've done nothing but pile into trouble ever since we found this wretched planet."

"Little bit different from Mars," Craig said. "Mars was paradise compared with this—and the people were human>! That's more than we can say of any of 'em here!"

"And you can't be surprised at whatever kind of nature you find possessed by people who live under such conditions as prevail on the planet," Appleton told him. "Besides which, my discoveries during the tour down here at least suggest that the planet is a comparatively young one, and, therefore, life is in a very undeveloped state. These people, all of them, are young children as compared with those on the Earth and on Mars, all of which is very interesting to me, though to you . . ."

"It's too exciting!" said Craig. "I'm not kicking, Chief, but I think we might as well think about going off on the way—home!"

"The first time you've said it all the while we've been away," Appleton said quietly, "and I think you're right. We'll sleep in the city here, and then go along to the bus. I'm tired out."

So it was agreed; and after a good sleep the two comrades, having indicated their desire to be going, were escorted by some of the Gill-folk down the channel which ended at the statue. A written message from Mackenzie had been brought a little while before that the obstruction had been removed and that the way was clear for the machine to go out. Naturally both Appleton and Craig were delighted over this—but their pleasure was very short-lived. It lasted no longer than it took them to get from the city to where they had left the Marsobus. For, when they arrived, there was not a sign of the machine.

"What the blue snakes does it mean?" exclaimed Appleton. "Here!" he rapped at one of the black men, forgetting in the excitement of the moment that the man could not understand him, "where's our machine gone?"

The fellow stared up at the man who held him by the bare shoulder, and Craig could not help laughing at the picture before him.

"Come off it, Chief," Teddy said. "The beggar doesn't understand. I'll find out." And he began to question him as well as he could with the aid of the few words that they had managed to learn meant something to the captive, and he got the answer he sought, for the man signed to him that the Marsobus had gone—gone down the channel through which it had come.

The fact left Appleton and Craig speechless for a while; they could only stare along the channel and wonder why this thing had been done.

"Not Mac, at any rate!" was the quiet reply. "Perhaps they've simply gone along to see if everything's clear, and—"

"Let's hope so," said the Professor, but there was little hope in his voice. "We've got to wait and see what happens. We can't go along the channel, unless we swim, because there's no bank to the river."

"But we could send some of these fellows," Craig suggested. "If we can make 'em understand!"

So, for the next few minutes Appleton was busy trying to get the Chief to understand what he wanted done. Eventually he succeeded in doing so, and several of the Gill-folk dived into their native element and went down the channel on the quest that meant so much for the adventurers.

CHAPTER 11
A Madman's Treachery

"BY Jove, mon, these fellows have got the hydraulic-crane stunt worked out all right!"

Mackenzie, left with Ashby while Appleton and Craig had gone on their tour of inspection, rubbed his hands as he saw the great rocks being lifted from the Marsobus, and told himself that it would not be long before the passage was free for their use.

"Yes, they have," Ashby said sullenly, and Mackenzie glanced at him a little dubiously.

"Cheer up, mon," he told him. "The Chief's told me that he's for makin' the move you want him to make as soon as he's done this little job he's on!"

"About time, too," growled Ashby, flinging himself down on the river bank, and lying there staring at the Gill-folk working.

"Don't like the look of him," Mackenzie ruminated. "Better keep my weather eye on him," which he did during the considerable time that elapsed before the last lump of rock was removed and the channel was clear. Sullen, glum, and silent, Ashby remained all this time, and it was only when he saw that the work was done that his eyes lighted up.

"Might as well get a message along to the Chief," Mackenzie said. "I'll scribble a note and get one of those fellows to take it to him.

"Why not take it yourself?" Ashby suggested casually; but Mackenzie shook his head.

"No," he said. "I promised the Chief I'd stay here. You can go if you like, but—"

"I'm staying!" Ashby almost yelled at him; and the engineer wanted to plant a blow between the slumbering eyes. He held himself in, however, by sheer sympathy with his nerve-racked companion, and, writing his note, gave it one of the Gill-men. The fellow seemed to understand what was required of him, and so, in due course, Appleton received the news that the obstruction had been removed. It was only a short time before Appleton and Craig made their start for the Marsobus; and, meanwhile, at Ashby's suggestion, he and Mackenzie, leaving the black outside, entered the machine with the idea of seeing that everything was ready for the return journey as soon as Appleton arrived.

There was not really much to do; but even that little was not completed, because, of a sudden, Mackenzie—who was bending over one of his beautiful engines—heard a soft pit-pat of feet, and looking casually over his shoulder had a vision of Ashby making a sudden spring at him, with an iron wrench in his hand.

Mackenzie turned swiftly, but he was too late. The wrench descended with a force that would have meant the death of the engineer but for the fact that, instead of striking him full upon the skull, it grazed the side of his head and face—with sufficient power behind it, however, to knock him to the floor insensible.

He turned as he heard a sound above him, and saw one of the Gill-men looking down through the trap-door.

If ever man had taken leave of his senses Ashby had; he whipped out his automatic and fired at the man, who disappeared with a loud cry; and Ashby, with the strange acumen that is often found in men whose brains have turned, ran up the steps and slid the trap-door to.

Chuckling to himself as he descended, he proceeded to carry out the rest of the atrocious plot he had been planning ever since Appleton had left.

He saw that the engines were in running order; and, satisfied on that point, and knowing how to work them, he put one of them in reverse, set it so that it worked automatically, and then, seating himself in the steersman's seat in the stern, began to pilot the Marsobus down the channel, the long beam of the fixed search light breaking the blackness.

"Would have kept me there!" Ashby chuckled, and then laughed aloud. "But I've done 'em—I've left them! It's home for me!"

In his madness he had forgotten that he did not know the way home; he had no more idea than a dead man what he would have to do to ensure taking the right direction through space; so do men overlook the most important things in their scheming.

So, in the paradise of his own ignorance, Ashby drove the Marsobus, remembering, strangely enough, that presently he was to find himself beneath the surface; and that beyond lay the great waste of water, above which was space, somewhere in which was the lodestone of his hopes—Earth.

On, and on, and on, and he had soon forgotten all about Mackenzie, lying in the cabin behind him; and for all the peril that appeared to be likely from the engineer, he might have been dead, as the blow had meant him to be.

Progress was slow; even in his madness Ashby was caution itself—and the Marsobus crawled her way through the channel.

How long he had been going Ashby did not know, when suddenly the engines ceased running. He rapped out an angry expletive, and tried to get the engine to start again. It refused; and he tried the others, but without avail. No mechanician, be found himself at a dead loss to know what to do; and it was then that he remembered Mackenzie.

"Ought not to have killed him," he muttered. "Should merely have stunned him. Want him now."

He moved across the cabin towards that in which he had left Mackenzie—and reached the door just as the engineer appeared in the doorway, a wild look in his eyes and his automatic in his hand.

"You hound!" Mackenzie barked, springing for him, his pistol thrust into his pocket, as, even under the sense of injury surging through him, he knew he could not do that> damage to Ashby.

His right arm shot, out and found its mark on Ashby's chin. The madman went staggering back, but with amazing agility maintained his balance and came back—to receive a blow upon the solar plexus that doubled him up and dropped him to the floor, where he lay writhing in pain. Mackenzie's pity stopped only at the point beyond which awaited death for Ashby, and he had no other mercy upon the madman: he simply fell upon him and finished the task with a crack on the skull that left Ashby an inert man. And Mackenzie, wiser in his sanity than even the craftiness of Ashby had made him in his madness, proceeded to bind his captive.

During the whole time—not long, be it said—of the fight, Mackenzie had been as one in a daze, the effects of the blow that he had received not altogether having worked off; and yet, when he went to the window near the steering scat, he was not altogether surprised to find that the Marsobus, instead of being in the broad space where it had been when last he had taken an interest in things, was in the narrow channel.

"Running away—leaving the Chief and Craig!" he muttered. "The mad fool! What did he think he was going to do?"

For Mackenzie was under no misapprehension as to the forlornness of the hope that it would be possible to reach the Earth without the aid of Appleton.

"Poor beggar—he's just mad," was the charitable conclusion to which Mackenzie came. "Reckon I'd better be going back. Ugh!"

He manipulated the mechanism that should have set the engine working, but discovered that it would not go. But, unlike Ashby, Mackenzie was an engineer, and it did not take him very long to find out what the matter was. In a little time the Marsobus was making her way once more along the channel, with Mackenzie peering through the glass in the wake of the streaming searchlight, which, after a while, threw into relief in the distance tiny specks that moved—specks which presently resolved themselves into swimmers, that Mackenzie recognized as Gill-folk.

"That means the Chief's come back and has sent to find the old bus!" the engineer said, grinning in spite of himself. "It should amuse these gentlemen who fancy themselves in aquatics to see the bus do what they can. I'll finish the journey below."

The whim of the moment tickled him, and he submerged the Marsobus, still with her searchlight going; and he was not a little amused to see the looks of astonishment on the faces of the Gill-men, who, when they saw the machine sinking, promptly dived below to find out what was really happening. They swarmed about the Marsobus and swam alongside her and in front of her as she made a careful way forward, the peculiar tiny lights that each of them carried being lost in the glare of the searchlight as it streamed through the moving waters.

So, with the strange escort, the Marsobus made her way, Mackenzie—more or less recovered from the effects of the blow given him by Ashby—thoroughly enjoying himself: both because of the triumph that he had won over the madman lying unconscious behind him, and because of the delight that he knew Appleton would feel when he saw the Marsobus again. And it goes without saying that not even the imagination of Mackenzie had been able to do justice to Appleton: for when the Marsobus, having traversed the length of the channel, rose to the surface, with the crowd of Gill-folk all about her, Appleton, no less than Teddy Craig, simply leapt.

"I told> you so, Teddy!" exclaimed Appleton. "They've been to make an inspection of the channel and . . . hallo! Mac. Glad to sec you!" he broke off as Mackenzie appeared on top.

"An' ye nearly didn't, mon!" the Scotsman said. "An' by St. Andrew I had no' too much faith I'd see ye! But I'll be tellin' ye all aboot it soon as I get ashore!"

"Where's Ashby?" Appleton demanded, when the engineer at last landed beside him. "And—good heavens, man, your head's just smothered with blood!"

"So's Ashby's!" was the laconic reply. "Not so sure I haven't broken his jaw—but I had to." And then he launched forth into a recital of what had happened, to which Appleton and Craig listened as calmly as they could.

"Same here," was Appleton's quiet agreement. "Goodness knows what might have happened if the engine hadn't given out, as apparently it did. Thank goodness it did. Now let's get aboard and away—after we've shown our friend the Chief here what the bus is like inside. He seems pretty agitated to have a look!"

The little man was gesticulating his request, but when Appleton invited him and he begun to scramble up the rope ladder, his people sent up shrill cries of alarm, as if they were afraid that their Chief was going to be kidnapped or swallowed for ever by the strange monster. The Chief, however, waved to them, and called out what was evidently an assurance regarding his safety, and then dropped into the machine and stood gazing in wonder at what was presented to his eyes.

As he toured the machine, he seemed to be looking for something, and it was only when Appleton saw him pounce upon a steel ball, that was part of the balancing equipment of the Marsobus, that the adventurers realized what the little man was seeking.

"Wants some of the bombs that put the wind up his enemies!" exclaimed Teddy; "well, he can't have 'em, since we haven't got any ourselves."

It took a great deal of sign-explanation to make the Chief understand that the steel ball was not a bomb, and that there were no such things available for him; and it was a very disappointed-looking individual who, after a while, made his departure from the Marsobus, and, standing amongst his people, bade farewell to the adventurers from another world.

"Any reason why you came under water, Mac?" Appleton inquired, as he started the machine.

"None, except my little joke on the Gillies," was the reply. "The surface is clear."

"Right; then we'll go that way," Appleton said; and the Marsobus crept down the channel until at last she came to where the water and the roof almost met. Then Appleton submerged, and with the great white blaze of light going ahead, the machine proceeded, occasionally rising in order to allow Appleton to see where he was—for he didn't know in the least how many miles the tunnel was long. But at last the periscope showed brightness in place of the blur that had meant the darkness of the tunnel, and there was a shout of delight from the adventurers as they saw the reflection in the mirror.

A moment or two later the searchlight gave out, and although Craig tried to get it to work again, he found it was impossible.

"All right—we'll go up without it and deal with it later. Uncover the windows so that we can see something of where we are."

Craig obeyed, and an all-too-small ring of light was thrown about the Marsobus. Nevertheless, Appleton was able to see something of what he wanted, and he found that the water near at hand was clear of icebergs. What lay behind the limit of the light, however, he did not know, and dared not use the periscope to find out lest it should be broken off; and so it was a blind craft that made a cautious ascent towards the surface—to break and find itself between what seemed to be two gigantic crystal castles.

When Appleton had had his look round, he liked the appearance of things still less: for what he discovered was that, instead of being between two icebergs, as be had expected, the Marsobus was actually in an iceberg!

"Here's a fine kettle of fish!" he exclaimed, and told what had happened. "We've simply risen up into an iceberg without knowing it—and I'm dead scared of it, because a berg hollowed out as this one is hasn't very long to exist in the mass. We must get out quickly."

That was very much easier said than done, as they all discovered very soon, for whereas they had, as by a miracle, ascended into the heart of the iceberg, to descend was no easy matter, since the drift of the mass of ice had to be taken into consideration. It was ticklish work—so ticklish, indeed, that Appleton sweated while he out in his seat and stared through the glass, trying to see the submerged sides of the berg. He realized that actually his best chance of accomplishing his purpose was in getting the Marsobus near to one of the sides, and steering by that; yet there was a danger in doing so, because a false move on his part might drive the machine into the ice—might even cause the smashing of the propeller. Nevertheless, Appleton took the risk, and was grateful to find that he was justified in doing so, because, taking the berg—now to be seen moving along at a fair rate—as his guide, he was able to judge the drift necessary for the Marsobus to make the descent without crashing into the floating prison.

So it was that his tense-nerved comrades watched him, wondering whether he would succeed; so it was that Appleton worked, until with a mirthless smile, he said:

Neither Mackenzie nor Craig ventured to make any other suggestion, and Appleton proceeded to do what he had proposed, with the result that it was not very long before the Marsobus was on the surface, but still not out of danger. For she had broken surface near several large bergs, which were actually bumping into one another, as though "crowding" each other for pride of place.

"Very pleasant, mon," Mackenzie said. "I . . . look out!" He ducked, involuntarily, as though he expected the great mass of ice that at that moment broke from one of the bergs to tumble on him and crush him to pulp.

"It's all right, Mac!" Appleton exclaimed. "That's falling clear of us. But it's certainly not healthy here. If—" he broke off suddenly, and his set mouth told the tale of the tension that was holding him; for, as the huge mass of ice fell from the top of the berg, it smashed into a smaller berg that was floating by like a yacht—and the air was filled with flying lumps of ice, one of which fell upon the propeller of the Marsobus.

The adventurers knew that something of this kind had happened even without having seen it, because the Marsobus suddenly ceased moving even at the very slow rate she had been previously notching; and they knew, every one of them, that before they could proceed farther they would have to repair that propeller with the fleet of icebergs seemingly intent upon bearing down on them.

"Tools out!" Appleton said quietly. "And while you're getting them, I'll go and inspect the damage. Perhaps it isn't much—just a little bend that we can put right temporarily and leave for proper treatment when we get out of this mess."

Out on the top of the Marsobus, now lying stationary except for the drift given her by the moving waters, Appleton stood for an instant or so, feasting upon the grim beauty of the scene before him: like crystal palaces the icebergs shone; the lines of some of them gave the impression of foreboding castles; yet others, with overhanging crowns, seemed as if they were about to tumble in thunderous weight.

The overhanging crowns of the icebergs seemed as
though they were about to tumble in thunderous weight.

CHAPTER 12
The End of the Troglodytes

PROFESSOR APPLETON did not waste any time in surveying a scene which, in other circumstances, would have aroused his scientific instinct, and have kept him engaged in a study of phenomena of undoubted value; his sole purpose at the moment was to see what was the matter with the machine on which depended all his hopes of ever being able to give to the world of his fellows the knowledge that he had acquired during the course of the most remarkable journey ever yet made by man.

Appleton began to walk along the Marsobus towards the propeller that had been damaged by the falling ice blocks; and, although he realised that every step might be the last—since the berg that had discarded its top was still in the process of disintegration, and huge blocks were tumbling about—he moved with the assurance born of acclimatising to danger, and at last reached the end of the Marsobus where was the shaft to which the propeller was attached.

It was a perilous position, indeed, that he had to take up in order to make the very necessary examination; he leant over the curve of the Marsobus and wrapped his arms around the shaft. It took him no more than a few minutes to see that the shafting, and not the propeller itself, was damaged. For which Appleton thanked the Fates.

It needed no second glance to tell him the reason of the erratic movements of the Marsobus: the propeller worked, but drove the machine in the wrong direction.

"It's a case of straightening it out as much as possible," he told Mackenzie, when he was once more back in the machine. "And it's not going to be too easy while the bus is drifting—there are too many icebergs about for my liking. We're absolutely in a field of 'em."

"Anyway, it's got to be done," said the engineer. "Help me run out the cradle and I'll get to work."

It was a task to which Appleton and Craig set themselves at once, fixing the light but very strong steel apparatus that, attached to the door at the top, stretched along the Marsobus to the propeller, from which was suspended a cradle into which Mackenzie got, and started to work with the various implements necessary to straighten out the shaft. It had to be heated first with the powerful blow-lamp, and then the engineer proceeded to straighten the steel, the while the Marsobus drifted between towering bergs, and both Appleton and Craig stood on guard with steel rods, which they used to keep the machine from crashing into any of the threatening masses. But, at last, the task was completed, and the propeller answered properly.

"Now that's done, I think our safest plan will be to take to the air," Appleton suggested. "It will mean we shan't have to watch out for bergs. I propose that we land on the ice-field and remain there while I work out the trajectory. That ought to please you, Ashby, old chap? Feeling better?" he asked the man, who had regained consciousness some little while before, and was lying in his bunk, securely trussed up to prevent his doing any more damage.

"I don't know what you're talking about!" Ashby said. "And I'd like to know why I'm like this?"

"Chief," he said quietly, "I know you'll understand, but I honestly don't know what it all means. I must have gone a bit loony. Anyway, I've been a bit of a cad."

Appleton did not speak for a moment or so; he was wondering whether Ashby was playing upon the "lost memory" string with craftiness; but he at last decided to give him the benefit of the doubt. Anyway, now that they were all together there would be little chance of his playing traitor again; while the fact, that it was the intention to make a start for Earth would be to the liking of Ashby, who surely would not attempt anything that might serve to interfere with the plan.

"It's all right, old man," he told him. "You've had a rotten time, and I sympathize with you. Cut that rope, Mac. We had to do it, you know, Ashby, for you were just berserk."

"Shake hands, all of you," Ashby said, when he was standing on his feet. "I'm sorry—and I hope you'll have no mercy if I try any more funny tricks."

They shook hands with him, and then, obedient to the demand of Appleton, the Marsobus rose straight into the air. High above the berg-filled sea the adventurers were able to look out across the crystal whiteness of the glacial territory, utterly devoid of life of any kind; a bleak wilderness, beneath which, most amazing thing of all, they knew lived beings who must surely be a race different from any other.

Appleton piloted the machine carefully, and at last brought it down upon the ice, well away from the sea lest any break-away of the mass should take them unawares.

"There's certainly nothing much to do while we are here," he told his comrades, "except get the bus into working order, or see that she is so. I can't say how long it will take me to make my observations and calculations, but you can bet I'm not wasting any time!"

But, even if he did not waste any time, the task took several nights and days, during which the adventurers remained in the Marsobus, only venturing out into the intense cold and the biting winds for exercise. At last, however, Appleton announced that he had finished his work, but with the statement he said:

"I'm sorry, fellows, but it's necessary for us to go back to that island we struck first. That's the point of departure. We'll make it a night landing, and so avoid coming into contact with the people there."

The news that they were to make a start on the return journey was sufficient to allay any apprehension that the adventurers might otherwise have felt at the idea of having to approach the country where they had had such a narrow escape.

"There's one thing about it, Chief," Teddy Craig said, when they were sitting down to a meal, "we do know what to look out for, and, in any case, as far us I'm concerned, I prefer folk who are more human than those people down under."

"Hear, hear," came the chorus from a trio of men with mouths full. During the course of the meal Appleton outlined his course of operations, and suggested that it would be a good plan while they were in their present position to try to get into touch with Horsman, whom they had left on Mars. They had been in communication several times while on the journey from the planet, but ever since they had been on the water world they had had no opportunity of making another attempt.

"Life's been too strenuous!" Appleton said, with a wry smile. "Anyway, we'll rig up the aerials here and see whether we have any better luck than we did aboard the bus."

It did not take long to get everything fixed up and, with the engines of the Marsobus running, Appleton made the necessary adjustments to the wireless apparatus that he judged should enable him to get into contact. It was all futile, however, for as a matter of fact the wireless would not work at all. It left Appleton thoroughly perplexed for some time, and, simply telling his companions the result of his efforts, he set himself to the task of trying to find out the reason. He made a number of experiments, not only with the wireless, but also with various other electrical instruments that the Marsobus carried and that he had not had any need to use while on the drowned planet; and in every case he had the same result; the apparatus would not work. In the end the conclusion to which he came was that there was something in the atmosphere of the planet that neutralized electricity.

"That explains a lot, fellows," he said to his comrades when he confided to them the results of his experiments. "It tells me why it was that we were so suddenly cut off from getting into touch with the Earth when we were on Mars. You noticed how we were able to communicate with Horsman up to the time we came within the atmosphere of this planet. Since then—well, you know what luck we've had. I shouldn't be at all surprised if, when we are out of the limits of the planet, we shall find ourselves able to get into touch with my friend Saunders on earth. However, that we shall know in due course. It's no use wasting more time here. Everything shipshape? That shaft quite all right again?"

"Then I reckon if we start now I can gauge the time of our arrival on the island so that we alight in the night. I took a note of the time to get here, and the distance it was, and the speed at which we went."

Nothing loath, the rest busied themselves in final preparations for departure, and in a little while the Marsobus was rising vertically from the waste of ice, Craig at one of the windows acting as photographer and getting some fine polar pictures. It was while he was doing this that he noticed something that made him hail Appleton from the bows of the Marsobus, and when the Professor, fixing the controls so that the machine worked automatically, got to the side of Craig, he was just in time to see in full swing what had first attracted Teddy's attention: a big smoke-cloud issuing from the ice many miles away.

"My goodness!" cried Appleton. "That's a volcanic eruption and—" He stopped speaking, held dumb for the moment by the terrific sight presented to him. Tremendous blocks of ice were being hurled into the air, on the crests, as it seemed, of scores of vast steam-clouds that suddenly became inky black and then burst into brilliant uprushing fires. Every man in the Marsobus, including the black, was staring at the amazing sight, awestruck by the splendour of its dread beauty. They were watching, had they but known it, a world in the process of dissipation; or, at least, the beginning of the end of its present character. It was no ordinary volcanic eruption, as Appleton very soon saw; the whole area was convulsed, and before very long there were literally hundreds of eruptions going on. Mountains of rock were being thrown up above the ice-crust that had existed for ages, and the ice itself was melting before the terrible heat and dissipating into vapour that very soon shrouded the scene—until the heat worked its will even with the vapour.

And, thousands of feet above, the men in the Marsobus looked down upon a seething cauldron as Nature carried out her tremendous and irresistible work. Through their powerful glasses they could see, as it were, into the heart of the world beneath them—aglow with vivid fires.

"And—we—we—might—have— been—there!" Teddy Craig gasped, grasping Appleton's arm; and in those words he voiced the feelings of all his comrades; but a comparatively short time before they had been beneath that very ice-crust that was now disappearing; had been living over that seething mass struggling its way through to freedom.

Dumb they fell again, these awe-struck spectators, as they stared down at the sight until even its terrific splendour became nauseating, and all were glad when Appleton said:

"Let's go and see if the island stands where it did. We must set our prisoner free. We can't take him with us."

Almost hysterical, none of them quite realized that the Professor was serious; but, as a matter of fact, the wide-spread area of the phenomenon had given rise to some anxiety in Appleton's mind as to what might be happening in other parts of the planet, and it was actually with some doubt in his mind that he turned the nose of the Marsobus in the direction in which he intended to go. This doubt and anxiety were increased as, during that long journey over the waste of waters, every now and then tremendous geysers uprose as though shot up by some giant fountain; and, also, there were to be seen islands which had not been there before—for Appleton was confident that he was following exactly the same route as he had done when he had steered the Marsobus towards the polar region.

"A world in the re-making!" he exclaimed on one occasion. "Unless it is a world in the last throes of destruction. A while ago I was almost sorry I had decided to stay here for any length of time; now, I am more than pleased. For, I assure you, fellows, that we are witnessing the greatest spectacle that humans have ever seen, and probably will ever see, again—and live to speak of it afterwards."

"And for my part," said dour Mackenzie, "I don't want to! Science—ugh—'tis all richt, Chief, when you read about it in books and potter about wi' test tubes an' so on; but when it comes to this—give me blessed ignorance."

"I had hoped by this time that you'd have acquired something of scientific enthusiasm, Mac," Appleton told him with a grin. "However, perhaps you're right. This sort of thing has its unpleasant side, even to a scientist. Here—it's time to slow down; we'll be making our port in daylight if we're not careful. We've been making too much speed: we'll be seen from the island if we go at this pace. Slow down almost to a drift, and we'll be able to time our approach."

"Always supposing it's there," Ashby said; he had remembered what Appleton said, and yet, queerly enough, considering the frame of mind he had been in for such a long time, he did not now display any bad feeling or show that he was in any way disgruntled. Actually—so queer is the human mind—if any one could be said to have enjoyed the recent experience—apart from Appleton, whose enjoyment had been of a purely academic kind—it was Ashby; he was the old, nonchalant Ashby, the globe-trotter who accepted life as he found it where he found it. Probably one thing that had more effect than anything else was the fact that he had remembered exactly what happened on that occasion when, on the capture of Appleton and the others, he had been left in the Marsobus and he had imagined that he had actually been marooned. And during the time since the adventurers had left the island he had really been brooding over what he fancied had been a dastardly intention on the part of his comrades; but with the regaining of memory of that hiatus, and an understanding of exactly what had taken place, he had become his old self. So it was that, having admitted it to his companions, the party became the closely united band of courageous men, who had gone through such thrilling experiences and made such remarkable discoveries in the interests of science.

For the first time Mackenzie and Craig realized what Appleton had meant when he spoke about the island "standing where it did," and they were both a little perturbed at the thought, although neither of them voiced it; they were willing to wait and see what happened, and they knew, from what Appleton had just said, they would not have to wait long. As if to give point to their fears they saw that the volcanic disturbance that had begun, or the effects of which they had first seen, at the polar region, was actually showing itself in the water beneath them—the water that was, comparatively, a few miles from the island towards which they were making. All of which served to bear out the suggestion made by Appleton. Was that suggestion founded on fact? If so, and the island no longer existed, none of them knew exactly what would happen; though it was certain that they would have to find a place on which to prepare the Marsobus for the journey through space as a "rocket."

"Cheer up, fellows!" Appleton said. "It will be all right anyway, I assure you. It's only a case of my working out a new calculation—although to do it we'd have to land on one of the new islands."

The cheeriness of Appleton served to lighten the spirits of his comrades, although they were still obsessed by the idea of being in a world of catastrophe. Still, life itself is hope—and they tried to show a bold front.

Night had fallen by now, and Appleton was having to rely upon the charts that he had made to tell him when he was above the island. It says much for the meticulous care with which the Professor had made his various calculations, and for the accuracy of the time and speed and distancing instruments, that, at what he had put down as the right moment, he saw the moving lights that he had expected to see—lights on the great floating dwellings of the people of the island.

During the last stage of the journey he had been agreeably surprised to notice that there were no volcanic disturbances, and this had inspired him with the hope that the island would be unaffected—a hope that was fulfilled when he looked through his night-glasses.

"It's all right, fellows!" he called out—but there was no need for him to do so, since every man was making his own observations. "We're going down now!"

Without a light or anything showing, the Marsobus, which was well over the great island, began to descend vertically; and her silent engines made the likelihood of her being seen very remote; and, knowing, as they did, that the only dwellings on the island were down on the shore, the adventurers had little anxiety about being discovered. Several hours of work confronted them, however; work for which light was needed. It was fortunate that in his earlier observations of the island Appleton had noted that inland the country had the formation of a cup, as though at some time there had been a lake or a sea. Once in the shelter of that, they could release their prisoner, and make their final preparations without too much risk.

CHAPTER 13
The Great Catastrophe

IT was with light hearts that the little band brought their machine to earth; the prisoner was bound for the time being, to obviate the chance of being able to get to his fellows before the adventurers were ready to make their start, and then the necessary work of adjusting the Marsobus was begun. The machine was a blaze of light, unavoidably so, and, to be protected against sudden attack, Appleton deputed Craig to climb the side of the "cup" and maintain a look out.

It was no easy task that the youngster was set; he was over a thousand feet above his comrades, looking down upon the island-world, the only bright spots being the far-off lights on the shore and the moving lights that told of the vessels riding at anchor.

Presently, however, he saw afar off a glow in the sky—a glow broken occasionally by vivid bursts, which Craig almost immediately realised were manifestations of the cataclysmic disturbance of which he had already seen so many signs.

"Getting nearer, after all," he muttered. "Must let the Chief know," and at once signalled back with his torch, the Morse code dashing the news down to Appleton.

"Keep me posted," was the Professor's reply. For several hours longer Craig remained in his position of sentry, occasionally flashing news to his comrades, and always closely watching for signs that might tell of approaching people. It was tedious work and trying to the nerves, and it was almost with a sigh of relief that Craig saw something that was of importance.

For, suddenly, the stretch of country between him and the coast was bathed in a white light, and, for the moment, he imagined that an eruption was taking place. Then he divined the explanation: a number of the brilliant, rocket-like things which had been used by the natives on that dramatic occasion when the Marsobus was captured had been hurled into the air, and in the white glare of them he saw, as he crouched low upon the ground, hundreds of figures rushing towards the shore, while the ships were alive with moving figures.

"Can't have discovered us!" Craig muttered. "Must be that they're scared over those outbursts at sea and—" He ceased even thinking, because the very power to think was taken from him for the time being. The earth upon which he was lying shook as though it had been made of jelly, and he was actually rolled down the side of the cup. He tried to save himself, but could not, and over and over he went until, bruised and shaken, he came to rest at the foot of the steep side. He scrambled to his feet, wondering at his ability to do that, and dashed as quickly as his trembling legs would allow him towards the light that told the position of the Marsobus.

He reached it, panting, almost exhausted, and certainly terrified—for the convulsions of the ground, which were still going on, had by now told their tale to him; he knew that the titanic death, or birth pains, had reached the island, and that at any moment it might go up in a great catastrophic upheaval that would spell the doom of his comrades and himself, and those people on the shore had felt the shakings and were rushing to their ships for safety.

He dropped, breathless, at the open door of the Marsobus, felt himself grasped by the collar and jerked to his feet, and heard the voice of Appleton say:

"It's the end. Chief—of all things!" Craig panted, as he was bundled into the Marsobus and heard the door slide to—and then was hurled across the machine, which rocked like a ship without a rudder. He heard Appleton cry: "Quickly, Mac; the engine!" and then all was blank as he struck the side of the Marsobus and dropped inert and unconscious.

Mackenzie sprang to obey the order that Appleton had just given him, for he had no illusions regarding what was happening. He knew, as Ashby knew, that the island was in the throes of the mighty disturbance and that the shakings which they had felt were the warnings of more serious things to come. Therefore Mackenzie breathed a prayer of thankfulness that the toil of the past hours had completed the preparations for departure and that the Marsobus could be started. Appleton himself, the moment he had hauled Craig into the machine, flew to the pilot's cabin and, as he heard the slight purr of the engine, pulled the lever that caused the Marsobus to rise straight up for a few yards, and was about to bring into operation the apparatus that turned the machine into a self-propelling rocket, when there was a terrific roar outside and the machine was bathed in a vivid red light that for the moment blinded the men inside as they looked through the uncovered windows.

"It's come!" breathed Appleton. "And—my goodness!" he cried as he saw the inclinator in front of him make a startling swing. He made a terrific effort to regain control of the machine—for he realized that the explosion below had shot the Marsobus up hundreds of feet, and that it was now rocking about on an uneven keel. "Power, Mac!" he shouted. But there was no answer either of voice, or of additional power, and, half-sensing that something must have happened to the engineer, Appleton realized that whatever was to be done must be his own unaided work. He played upon the delicate mechanism of his invention, and, watching the instruments before him with eyes that seemed to be looking at death itself, the Professor fought against the clutching power that, unseen, seemed to be trying to carry the Marsobus to its doom.

In the machine behind him there was being enacted a drama as grim as his own. Mackenzie had sprung for his engine the moment that Appleton had hauled Craig inside, while Craig went to the door and proceeded to fasten it. All of them had forgotten the native who a little while before had been told that he was to be set free, and had been unbound. When he realized, however, that after all he was not to go—there had been no opportunity to make him understand by the laborious sign method the reason why—he was seized with a great rage. He leapt at Ashby, who drove him back with a terrific blow that ought to have felled him, but which, instead, increased his anger. Crafty in his madness, the man slunk off into the engine-room, seized a heavy wrench, and dealt Mackenzie a blow from behind just, as the engineer had started his engine. Then, with a low chuckle, the black sprang into the main cabin again, striking out at Craig, who had been only partially stunned and had regained his feet in time to hear Ashby say:

Craig got the full force of the blow, and the edge of the wrench out into his head; he dropped to the floor on the instant, and Ashby, leaving the door not properly fastened, jumped for the black. The wrench flashed again, and Ashby only just succeeded in dodging it, so that the blow, instead of smashing upon his head, glanced down his left shoulder, numbing the arm. As he staggered back his antagonist leapt for the door, the method of opening which he was familiar with through having seen it done so often during his captivity. It slid open to his touch, and Ashby rushed towards him, intent on saving the man from the death that his own madness was driving him to. The man turned as he heard the footsteps behind, his right arm went up ready to drive another blow at Ashby, who, leaping, knocked aside the arm and tried to seize the man by the throat. The black divined his intention and dodged; then before Ashby realized it he was making the jump—to death. Even then Ashby tried to save him, but as he made to clutch him the man swung the wrench backwards and gave him a crack. It missed, however, and the action cost the man just the second of time that Ashby needed to grasp him by the swordfish gear on his head as he was slipping over the side. The tug of the falling man well-nigh pulled Ashby out after him, and it was only with great presence of mind that the would-be rescuer saved himself by curling his leg about the upright rail by the side of the door.

"Mac—quickly!" Ashby called out, and wondered greatly at getting no answer, knowing nothing of what had happened in the engine-room. Craig, he knew, was helpless, and after calling once more he realized that if the madman was to be saved, it must be done by himself alone.

But there was to be no saving. Something struck Ashby—he didn't know it, but it was the wrench which the man swung upwards. The blow knocked Ashby senseless, but at the same time the violent action served to snap the ties that bound the headpiece to the man, and he dropped into space and to death, leaving Ashby hanging out of the Marsobus, saved from the doom below only by that leg curled around the rail.

Appleton, who had heard those two cries of Ashby's, had not dared to leave his work to see what was happening; all his thoughts were concentrated upon the task of regaining control of the Marsobus and holding it in motion with the very small amount of power that was the result, if he had but known it, of Mackenzie having been interrupted by the black man.

Despite the seriousness of the situation, perhaps indeed because of it, Appleton had been cool and calculating all through, and even as he strove with and for the mighty child of his brain he was thinking of the black man who was still aboard—the man he had wanted to leave with his own follows, but whom he had decided to keep rather than send him to almost certain death by leaving him on the troubled island.

"He'll cause something of a stir when we get him back home," the Professor muttered. "I—ah—" He broke off suddenly, forgetting everything else but the fact that at last he had felt the machine respond to his touch.

"We've won!" he breathed, and drove the machine higher and higher above the flaming turmoil of destruction of which he had caught glances as the Marsobus was rioting like a wild thing before he had found himself its master again. And now he could look down upon it and wonder at the miracle that had snatched him and his comrades from the doom.

His comrades—Appleton remembered them. He had had them but vaguely in mind before, and now he realized the grim silence of those cabins behind him—silence that must mean something.

Appleton left his seat, and the Marsobus, with her mechanism fixed, hovered over the chaos below, while the Professor went into the cabin where, by right, Ashby and Craig should have been working. They were there, it is true, but they were not working, and at the sight of them Appleton gasped.

Craig was lying face down upon the floor, with a trickle of blood about his head; Appleton did not in that tense moment notice that Ashby was hanging half out of the door in the side of the machine, one leg curled curiously around the upright hand rail close by.

Appleton went into the engine-room—and laughed hysterically when he saw Mackenzie lying over one of the engines, limp and unconscious.

CHAPTER 14
Homeward-Bound!

APPLETON lifted the form from the engine and ran hurriedly over his comrade, found that he was still alive, and then, at the sound of a groan from the cabin behind him, he was out of the engine-room—to see, for the first time, Ashby curled up in his precarious position. Alive at once to the danger, Appleton leapt across the cabin and hauled Ashby from the danger—to find in one of the man's hands the swordfish headgear that had been worn by the black man.

"So that's the explanation," Appleton exclaimed, as it came to him in a flash that the native, probably stricken with terror, had taken the opportunity given by the temporary mishap to the machine to make a bold bid for freedom—freedom which meant death.

For the time being, however, Appleton, after closing the door and making a rapid search to make sure that the black was not in the Marsobus, left the consideration of this problem and devoted himself to the care of his comrades.

It was no small labour that presented itself to him. Ashby had received a heavy blow upon the head, and it took some considerable time to bring him round—and even then he was hazed and unable to assist Appleton with the others, who, however, were in due course brought back to consciousness. Craig had received the most severe handling. The weapon had bitten deeply enough to cause a bad wound that bled freely, and when he did recover he was weak from loss of blood.

"What happened, fellows?" Appleton asked, although he thought that he knew at least the broad outline of the story. It was Craig who told him—Craig who shuddered as he spoke and visualized those grim moments when he had hung out of the Marsobus, staring at the swaying figure and the lurid terror below.

"Well, the poor wretch chose his own death, even although he didn't realize it," Appleton said when the tale was done. "And he might have sent us to ours, too, because the little power that the engine was giving made it a terrific fight to get the machine through. Still. I managed it, and we're bound for home."

They were like hysterical school-children, those four men who had faced so much danger so courageously, at the thought of home.

"Have you set her on the course, Chief?" Mackenzie asked, but Appleton told him that he had only been able to get the Marsobus in hand and that she was hovering over the island still.

He went back to his steering-cabin and sat in front of the intricate charts that he had worked out. And Craig, sitting near him, watched him as he worked—watched the instruments move, and the numerous dials of wonderful mechanisms register the movements of the Marsobus as Appleton manoeuvred her.

And down below the war of nature was proceeding with terrify intensity. Ashby, who had nothing else to do, was staring down at it, held fascinated by the increasing wonder of the spectacle as the area of disturbance widened, until at last there was nothing at all to be seen except the vivid flames of spouting fire.

"Looks very like the end." he muttered. "Shouldn't be surprised if the whole jolly world went out." And he was thankful to the fates that had enabled him and his companions to get clear, even although there were great things yet to happen.

Ashby knew what that meant even before the Marsobus, responding to the additional power exerted by the engines, shot rocket-like into space. And Appleton came from his cabin and joined Ashby in the stern; after him came Craig, and then Mackenzie—to catch the last close glimpse of the world on which so many strange things had happened to them.

And even as they watched, the vivid glow that had been stationary before began to move. It went like a stream of flame, with a ball of light at its head.

"It's no longer a drowned planet, fellows," Appleton said quietly. "It's a burnt one."

For a time no one else spoke, but one after another hands grasped hands, and these men, driving through space at an incredible speed, were inwardly thanking providence that they had been snatched from the fate that had overtaken the unfortunate people on the drowned planet.

"Presently we'll try a little experiment," came Appleton's voice after a while, and all were thankful that the silence was broken. "We'll see if we can get into touch with Horsman. With that planet gone, and its disturbing influence no longer present, we ought to be able to do so."

He moved to the wireless cabin, and for a long time was engaged in working the apparatus—tense with expectation, the others waiting for him to announce the result.

"Something—coming—through," Appleton whispered at long last, and his comrades crowded closer round him. Silence then, except for the sounds made by the wireless—sounds that presently were translated.

"Been trying to get you," the message ran. "Thought mishap taken place. Thank heaven not. What's happened?"

In as brief a compass as he could, Appleton wirelessed back something of the events that had taken place since last he had been in touch with Horsman, and then demanded a recounting of what had happened to the man left upon Mars.

"Yes," the answer came back. "I've quite recovered from my wound, and Hoomri sanctioned the wedding at once—on conditions that as soon as I have heard that you have arrived back at Earth I shall cease communicating. I've got to become a Martian of the Martians."

Much more did Horsman have to tell, both on that occasion and the many others on which, during the long journey, the adventurers got into touch with him—while Appleton, after a considerable amount of trying, succeeded in getting into communication with his friend, Professor Saunders, who had worked with him in the invention of the Marsobus and at carrying out the plans of the great adventure.

Piece by piece Appleton gave news of the expedition, in turn receiving information from Saunders. Not the least amusing now!—was that which told him that the world had, directly communications were cut off with Saunders, pronounced Appleton a mad fool for having made the venture, and that Saunders was a charlatan who had tried to deceive the world by saying that he had ever been in touch with the adventurers. The world had said that Appleton had failed—and he and his companions gone to their deaths.

"And now," Saunders said, "that I have told them that I have found you again, and that you are on the way back, they put me down not only as a rogue, but as a mad rogue! 'The idea of my imagining they would believe me!' they say. Of course, the papers have got streaming and screaming headlines about it all. There are a thousand arguments going on in the Press and the clubs. Incidentally, they're holding you responsible for the marooning of Horsman on Mars—if it's at all true, they say. So, you see, there's quite a little cauldron on the brew for you when you get back."

All of which naturally amused Appleton not a little and served to help drive away the occasional boredom of the terrific journey. Also, what time he was not making observations and recording them he was sitting at his typewriter compiling the thrilling story that was to be the form in which the account of the expedition was first to be given to the world: that other book, the earnestly scientific one, was to come later.

Actually, the first account was compiled not merely from the diaries that Appleton had kept, but from the recollections of his comrades as well. And it was Teddy Craig who suggested one day that instead of waiting until the Earth was reached for the publication of the story, it would be as well to wireless at least some of it down to Saunders.

"You're right, Teddy," the Professor said, and forthwith began to flash through space the story which, despite the scepticism of the public, Saunders found no difficulty in selling all over the world.

"The editor fellows think that it makes exciting reading—as exciting as fiction," he told Appleton, "and they're paying a big price for it. And, by Jove, it's creating a stir. Folk swear I'm either the biggest liar yet, or else you're the most wonderful man who's over lived. I tell you, it's funny!"

In such fashion did the drawn out journey continue, the speed and distance registers of the Marsobus recording the increasing total of miles until at last there came the time when Appleton said:

"We shall be there in less than a week," he said it as casually as if he had been in a train and reckoning out how long it would take to reach the next station—and his comrades accepted the intimation quite as coolly.

"Am telling him to-day," was the reply. Within a few hours of that conversation the world of men had learned that the adventurers were nearing the Earth, and, as Saunders said later, everyone who possessed a telescope began to use it; and those who didn't, bought one—if one could judge from the newspaper reports and the fact that every manufacturer of glasses was booming his wares on the slogan: "Watch out for the Marsobus!"

Later still Appleton, having worked out the calculation almost to the minute—certainly to the hour—gave Saunders more exact time. And if the people on Earth were all eyes for the appearance of the monster machine, those inside it were all eyes for a close-up view of the Earth from which they had been absent long.

"The world's convinced!" came a message from Saunders on the day that Appleton was due. "Convinced because you've been seen—look out for some demonstration."

He did not tell what that demonstration was to be like, but the voyagers soon knew, for when they were still within five miles of the Earth they saw, as they peered through their glasses, flitting forms in the air which, as they got closer, they recognized as airships and aeroplanes—swarms of them, keeping the air to pay homage to the men who had done that which few had believed could ever be done.

"Fellows," said Appleton a little huskily, "thank God we've done it. No—wait a minute," as they seemed about to speak. "Let me finish. I want to say here, and not anywhere else, how much I appreciate your good comradeship. That's all—except that whatever of honour there may be coming to me, it is yours too. We've been friends, pals, throughout these years. We'll remain so."

Solemnly, as though performing some sacred rite, those four men shook hands, and there was not a dry eye in the Marsobus at that moment, even although the mouths of the four men were wreathed in smiles.

It was done—and airships and aeroplanes signalled back their welcome and formed a guard of honour about the machine that had accomplished the tremendous journey.

Like a stone now the Marsobus was dropping, by virtue of her helicopter, and at last she came to rest upon the ground inside the enclosure from which she had started.

Who shall describe the scene that followed? Attempts were made by journalists, as you can read in the newspapers of that time, but all failed. It was a scene that defied adequate description.

There was the Sovereign of Britain—there were hundreds of the most famous scientists in the world, who had hurried from all over the globe to be there to welcome their fellow Professor and his comrades.

But of all that great assembly there was one man whose presence meant more to Teddy Craig than any other. He was Doctor Mather, the headmaster of St. Christopher's School, at Potten: he stepped in front of that august crowd, and reaching out a hand took that of the now grown up person who, as a boy, had left school because of the accusation that had been levelled at him.

"Craig," said the Doctor, "forgive me! I was wrong—we were all wrong, and—here is Manson—who'll tell you all about it."

And Manson—Charlie Manson—who had been the bully at school and the enemy of Craig, stepped forward. A man now, was he—a man in more senses than one—as he stood before that company of men and said:

"Craig—your pardon. It was I who stole that which you were accused of stealing. I was a cad—I knew it immediately you disappeared, and I went to the Head and told him the truth. But it was too late; we could not trace you."

"Thanks, Manson," Teddy said quietly. "I was fed up—but I'm thanking the fates that put the wind up me, else I'd never have run away, and I'd never have been—where I've been. Don't worry."

There was a rousing cheer at that, and another as the two shook hands. Then suddenly Appleton turned to Saunders and said:

"What's the next item on the programme? I'm dead tired—honestly. I haven't really slept for about fifty hours I've been that anxious!"

"Well, I reckon you can't sleep yet," was the reply. "The royal car is outside, waiting to take you to the greatest banquet ever given in London. And you four are the guests of honour, so try to keep awake."

"Well, there's one thing I'm going to do first," Appleton told him. "My last message to—Horsman . . . even if the banquet gets cold!"

When His Majesty knew what was afoot he expressed a desire to send a message himself: and naturally Appleton sent it for him—sent it and received back the answer from Horsman:

"Thank his Majesty for me, and say that King Horsman, of Fambia, reciprocates the greeting. Hoomri has abdicated in favour of his son-in-law, and I am become indeed a Martian of the Martians! And now, old chap, good-bye and heaven bless you and the others!"

"Good-bye, my friend," Appleton sent back the message. He tried to send more than that, but there came no answer; and he realized that Horsman, the man who had elected to stay on Mars, had cut himself off for ever from the world that was really his own.

"Now I am ready—for anything," Appleton said, but there was not much of cheerfulness in his tone, or written on his face, as he walked by the side of his king through the lane formed by the most famous men of his time; his joy in achievement was tinged with sorrow at having said good-bye for the last time to a man who had been a very good friend.

And the first volume of the great work in which can be read the full story of the scientific discoveries on Mars and the Drowned Planet is dedicated to "My friend Horsman—King of Fambia," and neither Mackenzie nor Ashby nor Craig, who became rich men as the result of their share of the proceeds from books, and lectures delivered by Appleton, felt a touch of jealousy. For Horsman had been their friend, too, and often they think not a little wistfully of him and wonder how he fares.

ERIC WOOD
(FRANK KNOWLES CAMPLING)

THE DROWNED PLANET

THE SEQUEL TO "THE LOST PLANET"

Serialised in Chums, 28 May–13 August 1921

First e-book edition: Roy Glashan's Library, 2023
Version Date: 2023-10-01

Produced by Keith Emmett and Roy Glashan

All content added by RGL is proprietary and protected by copyright.

Click here for more books by this author

ALL ABOUT THE ADVENTURERS

TABLE OF CONTENTS

LIST OF ILLUSTRATIONS

CHAPTER 1
The People of the Water World

CHAPTER 2
Ashby's Last Hope

CHAPTER 3
Ashby Works Alone

CHAPTER 4
Adrift on the Ocean

CHAPTER 5
Beneath the Barrier of Ice

CHAPTER 6
In the Grip of the Torrent

CHAPTER 7
Appleton in the Hands of the "Gill-Men"

CHAPTER 8
War in the Great Cavern

CHAPTER 9
Secrets of the "Gill-Folks'" City

CHAPTER 10
Where Is the Marsobus?

CHAPTER 11
A Madman's Treachery

CHAPTER 12
The End of the Troglodytes

CHAPTER 13
The Great Catastrophe

CHAPTER 14
Homeward-Bound!

THE END

ERIC WOOD (FRANK KNOWLES CAMPLING)

THE DROWNED PLANET

THE SEQUEL TO "THE LOST PLANET"

Serialised in Chums, 28 May–13 August 1921 First e-book edition: Roy Glashan's Library, 2023 Version Date: 2023-10-01 Produced by Keith Emmett and Roy Glashan All content added by RGL is proprietary and protected by copyright. Click here for more books by this author

ALL ABOUT THE ADVENTURERS

TABLE OF CONTENTS

LIST OF ILLUSTRATIONS

CHAPTER 1 The People of the Water World

CHAPTER 2 Ashby's Last Hope

CHAPTER 3 Ashby Works Alone

CHAPTER 4 Adrift on the Ocean

CHAPTER 5 Beneath the Barrier of Ice

CHAPTER 6 In the Grip of the Torrent

CHAPTER 7 Appleton in the Hands of the "Gill-Men"

CHAPTER 8 War in the Great Cavern

CHAPTER 9 Secrets of the "Gill-Folks'" City

CHAPTER 10 Where Is the Marsobus?

CHAPTER 11 A Madman's Treachery

CHAPTER 12 The End of the Troglodytes

CHAPTER 13 The Great Catastrophe

CHAPTER 14 Homeward-Bound!

THE END

ERIC WOOD
(FRANK KNOWLES CAMPLING)

Serialised in Chums, 28 May–13 August 1921

First e-book edition: Roy Glashan's Library, 2023
Version Date: 2023-10-01

Produced by Keith Emmett and Roy Glashan

All content added by RGL is proprietary and protected by copyright.

Click here for more books by this author

CHAPTER 1
The People of the Water World

CHAPTER 2
Ashby's Last Hope

CHAPTER 3
Ashby Works Alone

CHAPTER 4
Adrift on the Ocean

CHAPTER 5
Beneath the Barrier of Ice

CHAPTER 6
In the Grip of the Torrent

CHAPTER 7
Appleton in the Hands of the "Gill-Men"

CHAPTER 8
War in the Great Cavern

CHAPTER 9
Secrets of the "Gill-Folks'" City

CHAPTER 10
Where Is the Marsobus?

CHAPTER 11
A Madman's Treachery

CHAPTER 12
The End of the Troglodytes

CHAPTER 13
The Great Catastrophe

CHAPTER 14
Homeward-Bound!