Chapter I.Contents

THE LAST OF THE EARTH.

Finding that they were rapidly swinging towards their proper course, and that the earth in its journey about the sun would move out of their way, they divided their power between repelling the body they had left and increasing the attraction of the moon, and then set about getting their house in order.

Bearwarden, having the largest appetite, was elected cook, the others sagely divining that labour so largely for himself would be no trial. Their small but business-like-looking electric range was therefore soon in full blast, with Bearwarden in command. It had enough current to provide heat for cooking for four hundred hours, which was an ample margin, and it had this advantage, that, no matter how much it was used, it could not exhaust the air as any other form of heat would.

There were also a number of sixteen-candle-power incandescent lamps, so that when passing through the shadow of a planet, or at night after their arrival on Jupiter, their car would be brightly illuminated. They had also a good search-light for examining the dark side of a satellite, or exploring the spaces in Saturn's rings. Having lunched sumptuously on canned chicken soup, beef a la jardiniere, and pheasant that had been sent them by some of their admirers that morning, they put the bones and the glass can that had contained the soup into the double-doored partition or vestibule, placing a large sheet of cardboard to act as a wad between the scraps and the outside door. By pressing a button they unfastened the outside door, and the articles to be disposed of were shot off by the expansion of the air between the cardboard disk and the inside door; after which the outside door was drawn back to its place by a current sent through a magnet, but little power being required to reclose it with no resisting atmospheric pressure. As the electricity ran along a wire passing through a hermetically sealed opening in the floor, there was no way by which more air than that in the vestibule could escape; and as the somewhat flat space between the doors contained less than one cubic foot, the air-pressure inside the Callisto could not be materially lessened by a few openings.

"By filling the vestibule as full as possible," said Bearwarden, "and so displacing most of its air, we shall be able to open the outside door oftener without danger of rarefaction."

The things they had discharged flew off with considerable speed and were soon out of sight; but it was not necessary for them to move fast, provided they moved at all, for, the resistance being nil, they would be sure to go beyond the range of vision, provided enough time was allowed, even if the Callisto's speed was not being increased by apergy, in which case articles outside and not affected would be quickly left behind.

The earth, which at first had filled nearly half their sky, was rapidly growing smaller. Being almost between themselves and the sun, it looked like a crescent moon; and when it was only about twenty times the size of the moon they calculated they must have come nearly two hundred thousand miles. The moon was now on what a sailor would call the starboard bow--i. e., to the right and ahead. Being a little more than three quarters full, and only about fifty thousand miles off, it presented a splendid sight, brilliant as polished silver, and about twenty-five times as large as they had ever before seen it with the unaided eye.

It was just ten hours since they had started, and at that moment 9 A. M. in New York; but, though it was night there, the Callisto was bathed in a flood of sunlight such as never shines on earth. The only night they would have was on the side of the Callisto turned away from the sun, unless they passed through some shadow, which they intended to avoid on account of the danger of colliding with a meteor in the dark. The moon and the Callisto were moving on converging lines, the curve on which they had entered having swung them to the side nearest the earth; but they saw that their own tremendous and increasing speed would carry them in front of the moon in its nearly circular orbit. Wishing to change the direction of their flight by the moon's attraction, they shut off the power driving them from the earth, whereupon the Callisto turned its heavy base towards the moon. They were already moving at such speed that their momentum alone would carry them hundreds of thousands of miles into space, and were then almost abreast of the earth's satellite, which was but a few thousand miles away. The spectacle was magnificent. As they looked at it through their field glasses or with the unaided eye, the great cracks and craters showed with the utmost clearness, sweeping past them almost as the landscape flies past a railway train. There was something awe-inspiring in the vast antiquity of that furrowed lunar surface, by far the oldest thing that mortal eye can see, since, while observing the ceaseless political or geological changes on earth, the face of this dead satellite, on account of the absence of air and water and consequent erosion, has remained unchanged for bygone ages, as it doubtless will for many more.

They closely watched the Callisto's course. At first it did not seem to deflect from a straight line, and they stood ready to turn on the apergetic force again, when the car very slowly began to show the effect of the moon's near pull; but not till they had so far passed it that the dark side was towards them were they heading straight for Jupiter. Then they again turned on full power and got a send-off shove on the moon and earth combined, which increased their speed so rapidly that they felt they could soon shut off the current altogether and save their supply.

"We must be ready to watch the signals from the arctic circle," said Bearwarden. "At midnight, if the calculations are finished, the result will be flashed by the searchlight." It was then ten minutes to twelve, and the earth was already over four hundred thousand miles away. Focusing their glasses upon the region near the north pole, which, being turned from the sun, was towards them and in darkness, they waited.

"In this blaze of sunlight," said Cortlandt, "I am afraid we can see nothing."

Fortunately, at this moment the Callisto entered the moon's tapering shadow.

"This," said Ayrault, "is good luck. We could of course have gone into the shadow; but to change our course would have delayed us, and we might have lost part of the chance of increasing our speed."

"There will be no danger from meteors or sub-satellites here," said Bearwarden, "for anything revolving about the moon at this distance would be caught by the earth."

The sun had apparently set behind the moon, and they were eclipsed. The stars shone with the utmost splendour against the dead-black sky, and the earth appeared as a large crescent, still considerably larger than the satellite to which they were accustomed. Exactly at midnight a faint phosphorescent light, like that of a glow-worm, appeared in the region of Greenland on the planet they had left. It gradually increased its strength till it shone like a long white beam projected from a lighthouse, and in this they beheld the work of the greatest search-light ever made by man, receiving for a few moments all the electricity generated by the available dynamos at Niagara and the Bay of Fundy, the steam engines, and other sources of power in the northern hemisphere. The beam lasted with growing intensity for one minute; it then spelled out with clean-cut intervals, according to the Cable Code: "23° no' 6". The southern hemisphere pumps are now raising and storing water at full blast. We have already begun to lower the Arctic Ocean."

Chapter II.Contents

SPACE AND MARS.

Never before had the travellers observed the stars and planets under such favourable conditions. No air or clouds intervened, and as the Callisto did not revolve on its axis there was no necessity for changing the direction of the glasses. After an hour of this interesting work, however, as it was already late at the longitude they had left on earth, and as they knew they had many days in space before them, they prepared to go to bed. When ready, they had only to pull down the shades; for, as apergy was not applied to them, but only to the Callisto, they still looked upon the floor as down, and closed the heavy curtains to have night or darkness. They found that the side of the Callisto turned constantly towards the sun was becoming very warm, the double-toughened glass windows making it like a greenhouse; but they consoled themselves with the thought that the sun's power on them was hourly becoming less, and they felt sure the double walls and thick upholstery would protect them almost anywhere within the solar system from the intense cold of space.

"We could easily have arranged," said Ayrault, "for night and day on alternate sides of the Callisto by having strips of metal arranged spirally on the outside as on the end of an arrow. These would have started us turning as slowly as we like, since we passed through the atmosphere at a comparatively low rate of speed."

"I am afraid," said Cortlandt, "the motion, however slow, would have made us dizzy. It would be confusing to see the heavens turning about us, and it would interfere with using the glasses."

The base and one side of the Callisto had constant sunshine, while the other side and the dome were in the blackest night. This dome, on account of its shape, sky windows, and the completeness with which it could be isolated, was an ideal observatory, and there was seldom a time during their waking hours for the rest of the journey when it was not occupied by one, two, or all the observers.

"There is something marvellous," said Cortlandt, "about the condition of space. Its absolute cold is appalling, apparently because there is nothing to absorb heat; yet we find the base of this material projectile uncomfortably warm, though, should we expose a thermometer in the shade in front, we know it would show a temperature of three hundred to four hundred degrees below zero--were the instrument capable of recording it."

Artificial darkness having been obtained, the travellers were soon asleep, Bearwarden's dreams being regaled with thoughts of his company's triumph; Ayrault's, naturally, with visions of Sylvia; while Cortlandt frequently started up, thinking he had already made some great astronomical discovery.

About 9 A. M., according to seventy-fifth meridian time, the explorers awoke feeling greatly refreshed. The tank in which the liquefied oxygen was kept automatically gave off its gas so evenly that the air remained normal, while the lime contained in cups absorbed the carbon dioxide as fast as they exhaled it. They had darkened those windows through which the sun was actually pouring, for, on account of the emptiness of the surrounding ether and consequent absence of diffusion of light, nothing but the inky blackness of space and the bright stars looked in at the rest. On raising the shades they got an idea of their speed. A small crescent, smaller than the familiar moon, accompanied by one still tinier, was all that could be seen of the earth and its satellite.

"We must," said Bearwarden, "be moving at the rate of nearly a million miles an hour, from the way we have travelled."

"We must be doing fully a million," replied Cortlandt, "for by this time we are pretty well in motion, having got a tremendous start when so near the moon, with it and the earth in line."

By steering straight for Jupiter, instead of for the place it would occupy ten days later, they knew they would swing past, for the giant planet, being in rapid motion, would advance; but they did not object to this, since it would give them a chance to examine their new world in case they wished to do so before alighting; while, if they preferred to land at once, they could easily change their course by means of the moons, the fourth, from which their car was named, being the one that they knew would be of most use. Their tremendous speed showed them they should have time for exploration on their arrival, and that they would reach their destination sooner than they had expected. The apergetic force being applied, as we have seen, only to the Callisto, just as power in starting is exerted on a carriage or railway car and only through it to the passengers, Ayrault and his companions had no unusual sensation except loss of weight, for, when they were so far from the earth, its attraction was very slight, and no other planet was near enough to take its place. After breakfast, wishing to reach the dome, and realizing that it would be unnecessary to climb, each in turn gave a slight spring and was obliged to put up his hands to avoid striking the roof. In the cool quiet of the dark dome it was difficult to believe that only twenty feet away the sun was shining with such intensity upon the metal base as to make it too hot on the inside to touch without gloves.

The first thing that attracted their attention was the size and brilliance of Mars. Although this red planet was over forty million miles from the earth when they started, they calculated that it was less than thirty million miles from them now, or five millions nearer than it had ever been to them before. This reduction in distance, and the clearness of the void through which they saw it, made it a splendid sight, its disk showing clearly. From hour to hour its size and brightness increased, till towards evening it looked like a small, full moon, the sun shining squarely upon it. They calculated that on the course they were moving they should pass about nine hundred thousand miles to the right or behind it, since it was moving towards their left. They were interested to see what effect the mass of Mars would have on the Callisto, and saw here a chance of still further increasing their speed. Notwithstanding its tremendous rate, they expected to see the Callisto swerve from its straight line and move towards Mars, whose orbital speed of nine hundred miles a minute they thought would take it out of the Callisto's way, so that no actual collision would occur even if their air-ship were left to her own devices.

Towards evening they noticed through their glasses that several apparently island peaks in the southern hemisphere, which was turned towards them, became white, from which they concluded that a snow-storm was in progress. The south polar region was also markedly glaciated, though the icecap was not as extensive as either of those at the poles of the earth.

"As the Martian winters must be fully as severe as ours," said Cortlandt, "on account of their length, the planet's distance from the sun, and the twenty-seven and a half degrees inclination of its axis, we can account for the smallness of its ice-caps only by the fact that its oceans cover but one fourth of its surface instead of three quarters, as on the earth, and there is consequently a smaller evaporation and rain and snow-fall."

They were too much interested to think of sleeping that night, and so, after dining comfortably returned to their observatory. When within four million miles of Mars the Callisto began to swerve perceptibly, its curve, as when near the moon beginning with a spiral. They swung on unconcernedly, however, knowing they could check their approach at any time. Soon Mars appeared to have a diameter ten times as great as that of the moon, and promised shortly to occupy almost one side of their sky. "We must be on the lookout for the satellites," said Cortlandt; "a collision with either would be worse than a wreck on a desert island."

They therefore turned their glasses in the direction of the satellites.

"Until Prof. Hall, at Washington, discovered the two satellites in 1877," he continued, "Mars was supposed to be without moons. The outer one, Deimos, is but six miles in diameter, and revolves about its primary in thirty hours and eighteen minutes, at a distance of fourteen thousand six hundred miles. As it takes but little longer to complete a revolution than Mars does to rotate on its axis, it remains in the Martial sky one hundred and thirty-two hours between rising and setting, passing through all the phases from new moon to full and back again four times; that is, it swings four times around Mars before going below the horizon. It is one of the smallest bodies discovered with a telescope. The inner one, Phobos, is considerably larger, having a diameter of about twenty miles. It is but twenty-seven hundred miles from Mars's surface, and completes its revolution in seven hours and thirty-eight minutes, which is shorter than any other known period, Jupiter's nearest moon being the next, with eleven hours and fifty-nine minutes. It thus revolves in less than a third of the time Mars takes to rotate, and must consequently rise in the west and set in the east, as it is continually running ahead of the surface of the planet, though the sun and all the other stars rise and set on Mars in the same way as on the earth."

When about fifteen thousand miles from Mars, they sighted Deimos directly ahead, and saw that they should pass on its left--i. e., behind--for it was moving across them. The sun poured directly upon it, making it appear full and showing all its features. There were small unevennesses on the surface, apparently seventy or a hundred feet high, which were the nearest approach to mountains, and they ran in ridges or chains. There were also unmistakable signs of volcanic action, the craters being large compared with the size of the planet, but shallow. They saw no signs of water, and the blackness of the shadows convinced them there was no air. They secured two instantaneous photographs of the little satellite as the Callisto swept by, and resumed their inspection of Mars. They noticed red and brownish patches on the peaks that had that morning turned white, from which they concluded that the snow had begun to melt under the warm spring sun. This strengthened the belief they had already formed, that on account of its twenty-seven and a half degrees inclination the changes in temperature on Mars must be great and sudden. So interested were they with this, that they did not at first see a large and bright body moving rapidly on a course that converged with theirs.

"We must be ready to repel boarders," said Bearwarden, observing it for the first time and fixing his glass upon it. "That must be Phobos."

Not ten miles off they beheld Mars's inner moon, and though their own speed caused them to overtake and rush by it like a whirlwind, the satellite's rapid motion in its orbit, in a course temporarily almost parallel with theirs, served to give them a chance the better to examine it. Here the mountain ranges were considerably more conspicuous than on Deimos, and there were boulders and loose stones upon their slopes, which looked as if there might at some time have been frost and water on its surface; but it was all dry now, neither was there any air. The evidences of volcanic action were also plainly visible, while a noticeable flattening at the poles showed that the little body had once rotated rapidly on its axis, though whether it did so still they had not time to ascertain. When abreast of it they were less than two miles distant, and they secured several instantaneous impressions, which they put aside to develop later. As the radius of Phobos's circle was far shorter than that of the parabolic curve they were making, it began to draw away, and was rapidly left behind. Applying the full apergetic force to Mars and the larger moon, they shot away like an arrow, having had their speed increased by the planet's attraction while approaching it, and subsequently by repulsion.

"Either of those," said Bearwarden, looking back at the little satellites, "would be a nice yacht for a man to explore space on. He would also, of course, need a sun to warm him, if he wished to go beyond this system, but that would not have to be a large affair--in fact, it might be smaller than the planet, and could revolve about it like a moon."

"Though a sun of that size," replied Cortlandt, "might retain its heat for the time you wished to use it, the planet part would be nothing like as comfortable as what we have here, for it would be very difficult to get enough air-pressure to breathe on so small a body, since, with its slight gravitation-pull, to secure fifteen pounds to the square inch, or anything like it, the atmosphere would have to extend thousands of miles into space, so that on a cloudy day you would be in darkness. It would be better, therefore, to have such a sun as you describe and accompany it in a yacht or private car like this, well stocked with oxygen and provisions. When passing through meteoric swarms or masses of solid matter, collision with which is the most serious risk we run, the car could follow behind its sun instead of revolving around it, and be kept from falling into it by partially reversing the attraction. As the gravitation of so small a sun would be slight, counteracting it for even a considerable time would take but little from the batteries."

"There are known to be several unclaimed masses," added Ayrault, "with diameters of a few hundred yards, revolving about the earth inside the orbit of the moon. If in some way two of these could be brought into sufficiently violent collision, they would become luminous and answer very well; the increase in bulk as a result of the consolidation, and the subsequent heat, about serving to bring them to the required size. Whenever this sun showed spots and indications of cooling, it could be made to collide with the solid head of some comet, or small asteroid, till its temperature was again right; while if, as a result of these accretions, it became unwieldy, it could be caused to rotate with sufficient rapidity on its axis to split, and we should have two suns instead of one."

"Bravo!" said Bearwarden. "There is no limit to what can be done. The idea of our present trip would have seemed more chimerical to people a hundred years ago than this new scheme appears now."

Thus they sat and talked, or studied maps and star-charts, or the stars themselves, while the hours quickly passed and they shot through space. They had now a straight stretch of over three hundred million miles, and had to cross the orbits of innumerable asteroids on the way. The apparent size of the sun had by this time considerably decreased, and the interior of the Callisto was no longer uncomfortably warm. They divided the day into twenty-four hours from force of habit, and drew the shades tightly during what they considered night, while Bearwarden distinguished himself as a cook.

Chapter III.Contents

HEAVENLY BODIES.

The following day, while in their observatory, they saw something not many miles ahead. They watched it for hours, and in fact all day, but notwithstanding their tremendous speed they came but little nearer.

"They say a stern chase is a long one," said Bearwarden; "but that beats anything I have ever seen."

After a while, however, they found they WERE nearer, the time taken having been in part due to the deceptive distance, which was greater than they supposed.

"A comet!" exclaimed Cortlandt excitedly. "We shall really be able to examine it near."

"It's going in our direction," said Ayrault, "and at almost exactly our speed."

While the sun shone full upon it they brought their camera into play, and again succeeded in photographing a heavenly body at close range. The nucleus or head was of course turned towards the sun; while the tail, which they could see faintly, preceded it, as the comet was receding towards the cold and dark depths of space. The head was only a few miles in diameter, for it was a small comet, and was composed of grains and masses of stone and meteoric iron. Many of the grains were no larger than peas or mustard-seeds; no mass was more than four feet in diameter, and all of them had very irregular shapes. The space between the particles was never less than one hundred times their masses.

"We can move about within it," said Ayrault, as the Callisto entered the aggregation of particles, and moved slowly forward among them.

The windows in the dome, being made of toughened glass, set somewhat slantingly so as to deflect anything touching them, and having, moreover, the pressure of the inside air to sustain them, were fairly safe, while the windows in the sides and base were but little exposed. Whenever a large mass seemed dangerously near the glass, they applied an apergetic shock to it and sent it kiting among its fellows. At these times the Callisto recoiled slightly also, the resulting motion in either being in inverse ratio to its weight. There was constant and incessant movement among the individual fragments, but it was not rotary. Nothing seemed to be revolving about anything else; all were moving, apparently swinging back and forth, but no collisions took place. When the separate particles got more than a certain distance apart they reapproached one another, but when seemingly within about one hundred diameters of each other they swung off in some other direction. The motion was like that of innumerable harp-strings, which may approach but never strike one another. After a time the Callisto seemed to become endowed with the same property that the fragments possessed; for it and they repelled one another, on a near approach, after which nothing came very near.

Much of the material was like slag from a furnace, having evidently been partly fused. Whether this heat was the result of collision or of its near approach to the sun at perihelion, they could not tell, though the latter explanation seemed most simple and probable. When at about the centre of the nucleus they were in semi-darkness--not twilight, for any ray that succeeded in penetrating was dazzlingly brilliant, and the shadows, their own included, were inky black. As they approached the farther side and the sunlight decreased, they found that a diffused luminosity pervaded everything. It was sufficiently bright to enable them to see the dark side of the meteoric masses, and, on emerging from the nucleus in total darkness, they found the shadow stretching thousands of miles before them into space.

"I now understand," said Bearwarden, "why stars of the sixth and seventh magnitude can be seen through thousands of miles of a comet's tail. It is simply because there is nothing in it. The reason ANY stars are obscured is because the light in the tail, however faint, is brighter than they, and that light is all that the caudal appendage consists of, though what produces it I confess I am unable to explain. I also see why the tail always stretches away from the sun, because near by it is overwhelmed by the more powerful light; in fact, I suspect it is principally in the comet's shadow that the tail is visible. It is strange that no one ever thought of that before, or that any one feared the earth's passing through the tail of a comet. It is obvious to me now that if there were any material substance, any gas, however rarefied, in this hairlike* accompaniment, it would immediately fall to the comparatively heavy head, and surround that as a centre." * Comet means literally a hair.

"How, then," asked Cortlandt, "do you account for the spaces between those stones? However slight gravitation might be between some of the grains, if it existed at all, or was unopposed by some other force, with sufficient time--and they have eternity--every comet would come together like a planet into one solid mass. Perhaps some similar force maintains gases in the distended tail, though I know of no such, or even any analogous manifestation on earth. If the law on which we have been brought up, that 'every atom in the universe attracts every other atom,' were without exceptions or modifications, that comet could not continue to exist in its present form. Until we get some additional illustration, however, we shall be short of data with which to formulate any iconoclastic hypothesis. The source of the light, I must admit, also puzzles me greatly. There is certainly no heat to which we can attribute it."

Having gone beyond the fragments, they applied a strong repulsion charge to the comet, creating thereby a perfect whirlpool among its particles, and quickly left it. Half an hour later they again shut off the current, as the Callisto's speed was sufficient.

For some time they had been in the belt of asteroids, but as yet they had seen none near. The morning following their experience with the comet, however, they went to their observatory after breakfast as usual, and, on pointing their glasses forward, espied a comparatively large body before them, a little to their right.

"That must be Pallas," said Cortlandt, scrutinizing it closely. "It was discovered by Olbers, in 1802, and was the second asteroid found, Ceres having been the first, in 1801. It has a diameter of about three hundred miles, being one of the largest of these small planets. The most wonderful thing about it is the inclination of its orbit--thirty-five degrees--to the plane of the ecliptic; which means that at each revolution in its orbit, it swings that much above and below the imaginary plane cutting the sun at its equator, from which the earth and other larger planets vary but little. This no doubt is due to the near approach and disturbing attraction of some large comet, or else it was flung above or below the ordinary plane in the catastrophe that we think befell the large planet that doubtless formerly existed where we now find this swarm. You can see that its path makes a considerable angle to the plane of the ecliptic, and that it is now about crossing the line."

It soon presented the phase of a half moon, but the waviness of the straight line, as in the case of Venus and Mercury, showed that the size of the mountains must be tremendous compared with the mass of the body, some of them being obviously fifteen miles high. The intense blackness of the shadows, as on the moon, convinced them there was no trace of atmosphere.

"There being no air," said Cortlandt, "it is safe to assume there is no water, which helps to account for the great inequalities on the body's surface, since the mountains will seem higher when surrounded by dry ocean-bottom than they would if water came halfway up their sides. Undoubtedly, however, the main cause of their height is the slight effect of gravitation on an asteroid, and the fact that the shrinking of the interior, and consequent folding of the crust in ridges, may have continued for a time after there was no longer water on the surface to cut them down.

"The temperature and condition of a body," continued Cortlandt, "seem to depend entirely on its size. In the sun we have an incandescent, gaseous star, though its spots and the colour of its rays show that it is becoming aged, or, to be more accurate, advanced in its evolutionary development. Then comes a great jump, for Jupiter has but about one fourteen-hundredth of the mass of the sun, and we expect to find on it a firm crust, and that the planet itself is at about the fourth or fifth period of development, described by Moses as days. Saturn is doubtless somewhat more advanced. The earth we know has been habitable many hundreds of thousands or millions of years, though three fourths of its surface is still covered by water. In Mars we see a further step, three fourths of its surface being land. In Mercury, could we study it better, or in the larger satellites of Jupiter or Saturn, we might find a stepping-stone from Mars to the moon, perhaps with no water, but still having air, and being habitable in all other respects. In our own satellite we see a world that has died, though its death from an astronomical point of view is comparatively recent, while this little Pallas has been dead longer, being probably chilled through and through. From this I conclude that all bodies in the solar system had one genesis, and were part of the same nebulous mass. But this does not include the other systems and nebulae; for, compared with them, our sun, as we have seen, is itself advanced and small beside such stars as Sirius having diameters of twelve million miles."

As they left Pallas between themselves and the sun, it became a crescent and finally disappeared.

Two days later they sighted another asteroid exactly ahead. They examined it closely, and concluded it must be Hilda, put down in the astronomies as No. 153, and having almost the greatest mean distance of any of these small bodies from the sun.

When they were so near that the disk was plainly visible to the unaided eye, Hilda passed between them and Jupiter, eclipsing it. To their surprise, the light was not instantly shut off, as when the moon occults a star, but there was evident refraction.

"By George!" said Bearwarden, "here is an asteroid that HAS an atmosphere."

There was no mistaking it. They soon discovered a small ice-cap at one pole, and then made out oceans and continents, with mountains, forests, rivers, and green fields. The sight lasted but a few moments before they swept by, but they secured several photographs, and carried a vivid impression in their minds. Hilda appeared to be about two hundred miles in diameter.

"How do you account for that living world," Bearwarden asked Cortlandt, "on your theory of size and longevity?"

"There are two explanations," replied Cortlandt, "if the theory, as I still believe, is correct. Hilda has either been brought to this system from some other less matured, in the train of a comet, and been captured by the immense power of Jupiter, which might account for the eccentricity of its orbit, or some accident has happened to rejuvenate it here. A collision with another minor planet moving in an orbit that crossed its own, or with the head of a large comet, would have reconverted it into a star, perhaps after it had long been cold. A comet may first have so changed the course of one of two small bodies as to make them collide. This seems to me the most plausible theory. Over a hundred years ago the English astronomer, Chambers, wrote of having found traces of atmosphere in some of these minor planets, but it was generally thought he was mistaken. One reason we know so little about this great swarm of minor planets is, that till recently none of them showed a disk to the telescope. Inasmuch as only their light was visible, they were indistinguishable from stars, except by their slow motion. A hundred years ago only three hundred and fifty had been discovered; our photographic star-charts have since then shown the number recorded to exceed one thousand."

Chapter IV.Contents

PREPARING TO ALIGHT.

That afternoon Ayrault brought out some statistical tables he had compiled from a great number of books, and also a diagram of the comparative sizes of the planets. "I have been not a little puzzled at the discrepancies between even the best authors," he said, "scarcely any two being exactly alike, while every decade has seen accepted theories radically changed." Saying which, he spread out the result of his labours (shown on the following pages), which the three friends then studied.

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"You see," Ayrault explained, "on Jupiter we shall need our apergetic outfits to enable us to make long marches, while on Saturn they will not be necessary, the increase in our weight as a result of that planet's size being considerably less than the usual load carried by the Roman soldier."

"I do not imagine," said Cortlandt, "we should long be troubled by gravitation without our apergetic outfits even on Jupiter, for, though our weight will be more than doubled, we can take off one quarter of the whole by remaining near the equator, their rapid rotation having apparently been given providentially to all the large planets. Nature will adapt herself to this change, as to all others, very readily. Although the reclamation of the vast areas of the North American Arctic Archipelago, Alaska, Siberia, and Antarctic Wilkes Land, from the death-grip of the ice in which they have been held will relieve the pressure of population for another century, at the end of that time it will surely be felt again; it is therefore a consolation to feel that the mighty planets Jupiter and Saturn, which we are coming to look upon as our heritage, will not crush the life out of any human beings by their own weight that may alight upon them."

Before going to bed that evening they decided to be up early the next day, to study Jupiter, which was already a brilliant object.

The following morning, on awakening, they went at once to their observatory, and found that Jupiter's disk was plainly visible to the naked eye, and before night it seemed as large as the full moon.

They then prepared to check the Callisto's headlong speed, which Jupiter's attraction was beginning to increase. When about two million miles from the great planet, which was considerably on their left, they espied Callisto ahead and slightly on their right, as Deepwaters had calculated it would be. Applying a mild repulsion to this--which was itself quite a world, with its diameter of over three thousand miles, though evidently as cold and dead as the earth's old moon--they retarded their forward rush, knowing that the resulting motion towards Jupiter would be helped by the giant's pull. Wishing to be in good condition for their landing, they divided the remainder of the night into watches, two going to sleep at a time, the man on duty standing by to control the course and to get photographic negatives, on which, when they were developed, they found two crescent-shaped continents, a speckled region, and a number of islands. By 7 A. M., according to Eastern standard time, they were but fifty thousand miles from Jupiter's surface, the gigantic globe filling nearly one side of the sky. In preparation for a sally, they got their guns and accoutrements ready, and then gave a parting glance at the car. Their charge of electricity for developing the repulsion seemed scarcely touched, and they had still an abundant supply of oxygen and provisions. The barometer registered twenty-nine inches, showing that they had not lost much air in the numerous openings of the vestibule. The pressure was about what would be found at an altitude of a few hundred feet, part of the rarefaction being no doubt due to the fact that they did not close the windows until at a considerable height above Van Cortlandt Park.

They saw they should alight in a longitude on which the sun had just risen, the rocky tops of the great mountains shining like helmets in its rays. Soon they felt a sharp checking of their forward motion, and saw, from the changed appearance of the stars and the sun, that they had entered the atmosphere of their new home.

Not even did Columbus, standing at the prow of the Santa Maria, with the New World before him, feel the exultation and delight experienced by these latter-day explorers of the twenty-first century. Their first adventures on landing the reader already knows.

Chapter V.Contents

EXPLORATION AND EXCITEMENT.

When they awoke, the flowers were singing with the volume of a cathedral organ, the chant rising from all around them, and the sun was already above the horizon. Finding a deep natural spring, in which the water was at about blood-heat, they prepared for breakfast by taking a bath, and then found they had brought nothing to eat.

"It was stupid of us not to think of it," said Bearwarden, "yet it will be too much out of our way to return to the Callisto."

"We have two rifles and a gun," said Ayrault, "and have also plenty of water, and wood for a fire. All we need is game."

"The old excuse, that it has been already shot out, cannot hold here," said Cortlandt.

"Seeing that we have neither wings nor pneumatic legs, and not knowing the advantage given us by our rifles," added Bearwarden, "it should not be shy either. So far," he continued, "we have seen nothing edible, though just now we should not be too particular; but near a spring like this that kind must exist."

"The question is," said the professor, "whether the game like warm water. If we can follow this stream till it has been on the surface for some time, or till it spreads out, we shall doubtless find a huntsman's paradise."

"A bright idea," said Bearwarden. "Let's have our guns ready, and, as old Deepwaters would say, keep our weather eye open."

The stream flowed off in a southeasterly direction, so that by following it they went towards the volcanoes.

"It is hard to realize," said the professor, "that those mountains must be several hundred miles away, for the reason that they are almost entirely above the horizon. This apparent flatness and wide range of vision is of course the result of Jupiter's vast size. With sufficiently keen sight, or aided by a good glass, there is no reason why one should not see at least five hundred miles, with but a slight elevation."

"It is surprising," said Ayrault, "that in what is evidently Jupiter's Carboniferous period the atmosphere should be so clear. Our idea has been that at that time on earth the air was heavy and dense."

"So it was, and doubtless is here," replied Cortlandt; "but you must remember that both those qualities would be given it by carbonic-acid gas, which is entirely invisible and transparent. No gas that would be likely to remain in the air would interfere with sight; water vapour is the only thing that could; and though the crust of this planet, even near the surface, is still hot, the sun being so distant, the vapour would not be raised much. By avoiding low places near hot springs, we shall doubtless have very nearly as clear an atmosphere as on earth. What does surprise me is the ease with which we breathe. I can account for it only by supposing that, the Carboniferous period being already well advanced, most of the carbonic acid is already locked up in the forests or in Jupiter's coal-beds."

"How," asked Bearwarden, "do you account for the 'great red spot' that appeared here in 1878, lasted several years, and then gradually faded? It was taken as unmistakable evidence that Jupiter's atmosphere was filled with impenetrable banks of cloud. In fact, you remember many of the old books said we had probably never seen the surface."

"That has puzzled me very much," replied Cortlandt, "but I never believed the explanation then given was correct. The Carboniferous period is essentially one of great forest growth; so there would be nothing out of the way in supposing the spot, notwithstanding its length of twenty-seven thousand miles and its breadth of eight thousand miles, to have been forest. It occurred in what would correspond to the temperate region on earth. Now, though the axis of this planet is practically straight, the winds of course change their direction, and so the temperature does vary from day to day. What is more probable than that, owing perhaps to a prolonged norther or cold spell, a long strip of forest lying near the frost line was brought a few degrees below it, so that the leaves changed their colours as they do on earth? It would, it seems to me, be enough to give the surface a distinct colour; and the fact that the spot's greatest length was east and west, or along the lines of latitude, so that the whole of that region might have been exposed to the same conditions of temperature, strengthens this hypothesis. The strongest objection is, that the spot is said to have moved; but the motion--five seconds--was so slight that it might easily have been an error in observation, or the first area affected by the cold may have been enlarged on one side. It seems to me that the stability the spot DID have would make the cloud theory impossible on earth, and much more so here, with the far more rapid rotation and more violent winds. It may also have been a cloud of smoke from a volcano in eruption, such as we saw on our arrival, though it is doubtful whether in that case it would have remained nearly stationary while going through its greatest intensity and fading, which would look as though the turned leaves had fallen off and been gradually replaced by new ones; and, in addition to this, the spot since it was first noticed has never entirely disappeared, which might mean a volcanic region constantly emitting smoke, or that the surface, doubtless from some covering whose colour can change, is normally of a different shade from the surrounding region. In any case, we have as yet seen nothing that would indicate a permanently clouded atmosphere."

Though they had walked a considerable distance, the water was not much cooled; and though the stream's descent was so slight that on earth its current would have been very slow, here it rushed along like a mountain torrent, the reason, of course, being that a given amount of water on Jupiter would depress a spring balance 2.55 times as much as on the earth.

"It is strange," said Ayrault, "that, notwithstanding its great speed, the water remains so hot; you would think its motion would cool it."

"So it does," answered the professor. "It of course cools considerably more in a given period--as, for instance, one minute--than if it were moving more slowly, but on account of its speed it has been exposed to the air but a very short time since leaving the spring."

Just before them the stream now widened into a narrow lake, which they could see was straight for some distance.

"The fact is," said Bearwarden, "this water seems in such haste to reach the ocean that it turns neither to right nor to left, and does not even seem to wish to widen out."

As the huge ferns and palms grew to the water's edge, they concluded the best way to traverse the lake would be on a raft. Accordingly, choosing a large overhanging palm, Bearwarden and Ayrault fired each an explosive ball into its trunk, about eighteen inches from the ground. One round was enough to put it in the water, each explosion removing several cubic feet of wood. By repeating this process on other trees they soon had enough large timber for buoyancy, so that they had but to superimpose lighter cross-logs and bind the whole together with pliable branches and creepers to form a substantial raft. The doctor climbed on, after which Bearwarden and Ayrault cast off, having prepared long poles for navigating. With a little care they kept their bark from catching on projecting roots, and as the stream continued to widen till it was about one hundred yards across, their work became easy. Carried along at a speed of two or three miles an hour, they now saw that the water and the banks they passed were literally alive with reptiles and all sorts of amphibious creatures, while winged lizards sailed from every overhanging branch into the water as they approached. They noticed also many birds similar to storks and cranes, about the size of ostriches, standing on logs in the water, whose bills were provided with teeth.

"We might almost think we were on earth," said Ayrault, "from the looks of those storks standing on one leg, with the other drawn up, were it not for their size."

"How do you suppose they defend themselves," asked Bearwarden, "from the snakes with which the water is filled?"

"I suspect they can give a pretty good account of themselves," replied Cortlandt, "with those teeth. Besides, with only one leg exposed, there is but a very small object for a snake to strike at. For their number and size, I should say their struggle for existence was comparatively mild. Doubtless non-poisonous, or, for that matter, poisonous snakes, form a great part of their diet."

On passing the bend in the lake they noticed that the banks were slightly higher, while palms, pine-trees, and rubber plants succeeded the ferns. In the distance they now heard a tremendous crashing, which grew louder as the seconds passed. It finally sounded like an earthquake. Involuntarily they held their breath and grasped their weapons. Finally, at some distance in the woods they saw a dark mass moving rapidly and approaching the river obliquely. Palms and pine-trees went down before it like straws, while its head was continually among the upper branches. As the monster neared the lake, the water at the edges quivered, showing how its weight shook the banks at each stride, while stumps and tree-trunks on which it stepped were pressed out of sight in the ground. A general exodus of the other inhabitants from his line of march began; the moccasins slid into the water with a low splash, while the boa-constrictors and the tree-snakes moved off along the ground when they felt it tremble, and a number of night birds retreated into the denser woods with loud cries at being so rudely disturbed. The huge beast did not stop till he reached the bank, where he switched his tail, raised his proboscis, and sniffed the air uneasily, his height being fully thirty feet and his length about fifty. On seeing the raft and its occupants, he looked at them stupidly and threw back his head.

"He seems to be turning up his nose at us," said Bearwarden. "All the same, he will do well for breakfast."

As the creature moved, his chest struck a huge overhanging palm, tearing it off as though it had been a reed. Brushing it aside with his trunk, he was about to continue his march, when two rifle reports rang out together, rousing the echoes and a number of birds that screeched loudly.

Chapter VI.Contents

MASTODON AND WILL-O'-THE WISPS.

Bearwarden's bullet struck the mammoth in the shoulder, while Ayrault's aim was farther back. As the balls exploded, a half-barrelful of flesh and hide was shot from each, leaving two gaping holes. Instantly he rushed among the trees, making his course known for some time by his roars. As he turned, Bearwarden fired again, but the ball flew over him, blowing off the top of a tree.

"Now for the chase!" said Ayrault. "There would be no excuse for losing him."

Quickly pushing their raft to shore and securing it to the bank, the three jumped off. Thanks to their rubber boots and galvanic outfits which automatically kept them charged, they were as spry as they would have been on earth. The ground all about them, and in a strip twelve feet wide where the mammoth had gone, was torn up, and the vegetation trodden down. Following this trail, they struck back into the woods, where in places the gloom cast by the thick foliage was so dense that there was a mere twilight, startling as they went numbers of birds of grey and sombre plumage, whose necks and heads, and the sounds they uttered, were so reptilian that the three terrestrials believed they must also possess poison fangs.

"The most highly developed things we have seen here," said Bearwarden, "are the flowers and fireflies, most of the birds and amphibians being simply loathsome."

As they proceeded they found tracks of blood, which were rapidly attracting swarms of the reptile birds and snakes, which, however, as a rule, fled at their approach.

"I wonder what can have caused that mammoth to move so fast, and to have seemed so ill at ease?" said the doctor. "His motive certainly was not thirst, for he did not approach the water in a direct line, neither did he drink on reaching it. One would think nothing short of an earthquake or a land-slide could trouble him." "There can be no land-slide here," said Ayrault, "for the country is too flat."

"And after yesterday's eruptions," added Bearwarden, "it would seem as though the volcanoes could have scarcely enough steam left to make trouble."

The blood-tracks, continuing to become fresher, showed them they were nearing the game, when suddenly the trail took a sharp turn to the right, even returning towards the lake. A little farther it took another sharp turn, then followed a series of doublings, while still farther the ground was completely denuded of trees, its torn-up and trampled condition and the enormous amount of still warm blood showing how terrific a battle had just taken place.

While they looked about they saw what appeared to be the trunk of a tree about four feet in diameter and six feet long, with a slight crook. On coming closer, they recognized in it one of the forefeet of the mammoth, cut as cleanly as though with a knife from the leg just above the ankle, and still warm. A little farther they found the huge trunk cut to slivers, and, just beyond, the body of the unfortunate beast with three of its feet gone, and the thick hide cut and slashed like so much paper. It still breathed, and Ayrault, who had a tender heart, sent an explosive ball into its skull, which ended its suffering.

The three hunters then surveyed the scene. The largest and most powerful beast they had believed could exist lay before them dead, not from the bite of a snake or any other poison, but from mechanical injuries of which those they had inflicted formed but a very small part, and literally cut to pieces.

"I am curious to see the animal," said Cortlandt, "capable of doing this, though nothing short of dynamite bombs would protect us from him."

"As he has not stopped to eat his victim," said Bearwarden, "it is fair to suppose he is not carnivorous, and so must have had some other motive than hunger in making the attack; unless we can suppose that our approach frightened him away, which, with such power as he must possess, seems unlikely. Let us see," he continued, "parts of two legs remain unaccounted for. Perhaps, on account of their shape, he has been able the more easily to carry or roll them off, for we know that elephant foot makes a capital dish."

"From the way you talk," said Cortlandt, "one would suppose you attributed this to men. The Goliath we picture to ourselves would be a child compared to the man that could cut through these legs, though the necessity of believing him to have merely great size does not disprove his existence here. I think it probable we shall find this is the work of some animal with incisors of such power as it is difficult for us to conceive of."

"There is no indication here of teeth," said Bearwarden, "each foot being taken off with a clean cut. Besides, we are coming to believe that man existed on earth during the greater part, if not the whole, of our Carboniferous period."

"We must reserve our decision pending further evidence," said Cortlandt.

"I vote we take the heart," said Ayrault, "and cook it, since otherwise the mammoth will be devoured before our eyes."

While Bearwarden and Ayrault delved for this, Cortlandt, with some difficulty, parted the mammoth's lips and examined the teeth. "From the conical projections on the molars," said he, "this should be classed rather as a mastodon than as a mammoth."

When the huge heart was secured, Bearwarden arranged slices on sharpened sticks, while Ayrault set about starting a fire. He had to use Cortlandt's gun to clear the dry wood of snakes, which, attracted doubtless by the dead mastodon, came in such numbers that they covered the ground, while huge pterodactyls, more venomous-looking than the reptiles, hovered about the opening above.

Arranging a double line of electric wires in a circle about the mastodon and themselves, they sat down and did justice to the meal, with appetites that might have dismayed the waiting throng. Whenever a snake's head came in contact with one wire, while his tail touched the other, he gave a spasmodic leap and fell back dead. If he happened to fall across the wires, he immediately began to sizzle, a cloud of smoke arose, and lie was reduced to ashes.

"Any time that we are short of mastodon or other good game," said Ayrault, "we need not hunger if we are not above grilled snake."

All laughed at this, and Bearwarden, drawing a whiskey-flask from his pocket, passed it to his friends.

"When we rig our fishing-tackle," he continued, "and have fresh fish for dinner, an entree of rattlesnake, roast mastodon for the piece de resistance, and begin the whole with turtle soup and clams, of which there must be plenty on the ocean beach, we shall want to stay here the rest of our lives."

"I suspect we shall have to," replied Ayrault "for we shall become so like Thanksgiving turkeys that the Callisto's door will be too small for us."

While they sat and talked, the flowers and plants about them softly began their song, and, as a visual accompaniment, the fire-flies they had not before noticed twinkled through the forest.

"My goodness!" exclaimed Cortlandt, "how time goes here! We started to get breakfast, and now it's growing dark."

Hastily cutting some thick but tender slices from the mastodon, and impaling them with the remains of the heart on a sharpened stake, they took up the wires, and the battery that had been supplying the current, and retraced their steps by the way they had come. Their rubber-lined cowhide boots protected them from all but the largest snakes, and as these were for the most part already enjoying their gorge, they trampled with impunity on those that remained in their path. When they had covered about half the distance to the raft, a huge boa-constrictor, which they had mistaken for a branch, fell upon Cortlandt, pinioning his arms and bearing him to the ground. Dropping their loads, Bearwarden and Ayrault threw themselves upon the monster with their hunting-knives with such vim that in a few seconds it beat a hasty retreat, leaving, as it did so, a wake of phosphorescent light.

"Are you hurt?" asked Bearwarden, helping him up.

"Not in the least," replied Cortlandt. "What surprises me is that I am not. The weight of that boa-constrictor would be very great on earth, and here I should think it would be simply crushing."

Groping their way through the rapidly growing darkness, they reached the raft without further adventure, and, once on the lake, had plenty of light. Two moons, one at three quarters and the other full, shone brightly, while the water was alive with gymnotuses and other luminous creatures. Sitting and living upon the cross-timbers, they looked up at the sky. The Great Bear and the north star had exactly the same relation to each other as when seen from the earth, while the other constellations and the Milky Way looked identically as when they had so often gazed at them before, and some idea of the immensity of space was conveyed to them. Here was no change; though they had travelled three hundred and eighty million miles, there was no more perceptible difference than if they had not moved a foot. Perhaps, they thought, to the telescopes--if there are any--among the stars, the sun was seen to be accompanied by two small, dark companions, for Jupiter and Saturn might be visible, or perhaps it seemed merely as a slightly variable star, in years when sun-spots were numerous, or as the larger planets in their revolutions occasionally intercepted a part of its light. As they floated along they noticed a number of what they took to be Will-o'-the-wisps. Several of these great globules of pale flame hovered about them in the air, near the surface of the water, and anon they rose till they hung above the trees, apparently having no forward or horizontal motion except when taken by the gentle breeze, merely sinking and rising.