Part 13 (2/2)
”I follow you,” said Bearwarden, ”and do not see how we could arrive at anything else. From Jupiter's low specific gravity, weighing but little more than an equal bulk of water, I should say the interior must be very hot, or else is composed of light material, for the crust's surface, or the part we see, is evidently about as dense as what we have on earth. These things have puzzled me a good deal, and I have been wondering if Jupiter may not have been formed before the earth and the smaller planets.”
”The discrepancies between even the best authorities,” replied Cortlandt, ”show that as yet but little has been discovered from the earth concerning Jupiter's real condition. The two theories that try to account for its genesis are the ring theory and the nebulous. We know that the sun is constantly emitting vast volumes of heat and light, and that, with the exception of the heat resulting from the impact of falling meteors, it receives none from outside, the princ.i.p.al source being the tremendous friction and pressure between the cooling and shrinking strata within the great ma.s.s of the sun itself. A seeming paradox therefore comes in here, which must be considered: If the sun were composed entirely of gas, it would for a time continue to grow hotter; but the sun is incessantly radiating light and heat, and consequently becoming smaller. Therefore the farther back we go the hotter we find the sun, and also the larger, till, instead of having a diameter of eight hundred and eighty thousand miles, it filled the s.p.a.ce now occupied by the entire solar system. Here is where the two theories start. According to the first, the revolving nebulous ma.s.s threw off a ring that became the planet Neptune, afterwards another that contained the material for Ura.n.u.s, and so on, the lightest substance in the sun being thrown off first, by which they accounted for the lightness of the four great planets, and finally Mars, the earth, and the small dense planets near the sun. The advocates of this theory pointed to Saturn's rings as an ill.u.s.tration of the birth of a planet, or, rather, in that case a satellite. According to this, the major planets have had a far longer separate existence than the minor, which would account for their being so advanced notwithstanding their size. This theory may again come into general acceptance, but for the present it has been discredited by the nebulous. According to this second theory, at the time the sun filled all the s.p.a.ce inside of Neptune's, orbit, or extended even farther, several centres of condensation were formed within the nebulous, gaseous ma.s.s. The greatest centre became the sun, and the others, large and small, the planets, which--as a result of the spiral motion of the whole, such as is now going on before our eyes in the great nebulae of fifty-one M.
Canuin venaticorum, and many others--began to revolve about the greatest central body of gas. As the separate ma.s.ses cooled, they shrank, and their surfaces or extreme edges, which at first were contiguous, began to recede, which recession is still going on with some rapidity on the part of the sun, for we may be sure its diameter diminishes as its density increases. According to either theory, as I see it, the major planets, on account of their distance from the central ma.s.s, have had longer separate existences than the minor, and are therefore more advanced than they would be had all been formed at the same time.
”This theory explains the practical uniformity in the chemical composition of all members of this system by a.s.suming that they were all once a part of the same body, and you may say brothers and sisters of the sun, instead of its offspring. It also makes size the only factor determining temperature and density, but of course modified by age, since otherwise Jupiter would have a far less developed crust than that with which we find it. I have always considered the period from the molten condition to that with a crust as comparatively short, which stands to reason, for radiation has then no check; and the period from the formation of the crust, which acts as a blanket, to the death of a planet, as very long. I have not found this view clearly set forth in any of the books I have read, but it seems to me the simplest and most natural explanation. Now, granted that the solar system was once a nebula, on which I think every one will agree--the same forces that changed it into a system of sun and planets must be at work on fifty-one M. Canum venaticorum, Andromeda, and ninety-nine M. Virginis, and must inevitably change them to suns, each with doubtless a system of planets.
”If, then, the condition of a nebula or star depends simply on its size, it is reasonable to suppose that Andromeda, Sirius, and all the vast bodies we see, were created at the same time as our system, which involves the necessity of one general and simultaneous creation day.
But as Sirius, with its diameter of twelve million miles, must be larger than some of the nebulae will be when equally condensed, we must suppose rather that nebulae are forming and coming into the condition of bright and dead stars, much as apples or pears on a fruit tree are constantly growing and developing, so that the Mosaic description of the creation would probably apply in point of time only to our system, or perhaps to our globe, though the rest will doubtless pa.s.s through precisely the same stages. This, I think, I will publish, on our return, as the Cortlandt astronomical doctrine, as the most rational I have seen devised, and one that I think we may safely believe, until, perhaps, through increased knowledge, it can be disproved.”
After they crossed a line of hills that ran at right angles to their course they found the country more rolling. All streams and water-courses flowed in their direction, while their aneroid showed them that they were gradually descending. When they were moving along near the surface of the ground, a delicious and refined perfume exhaled by the blue and white flowers, that had been growing smaller as they journeyed northward, frequently reached their nostrils. To Cortlandt and Bearwarden it was merely the scent of a flower, but to Ayrault it recalled mental pictures of Sylvia wearing violets and lilies that he had given her. He knew that the greatest telescopes on earth could not reveal the Callisto moving about in Jupiter's suns.h.i.+ne, as even a point of light, at that distance, and, notwithstanding Cortlandt's learning and Bearwarden's joviality, he felt at times extremely lonely.
They swept along steadily for fifty hours, having bright sunny days and beautifully moonlit nights. They pa.s.sed over finely rounded hills and valleys and well-watered plains. As they approached the ocean and its level the temperature rose, and there was more moisture in the air.
The plants and flowers also increased in size, again resembling somewhat the large species they had seen near the equator.
”This would be the place to live,” said Bearwarden, looking at iron mountains, silver, copper, and lead formations, primeval forests, rich prairies, and regions evidently underlaid with coal and petroleum, not to mention huge beds of aluminum clay, and other natural resources, that made his materialistic mouth water. ”It would be joy and delight to develop industries here, with no snow avalanches to clog your railroads, or icy blizzards to paralyze work, nor weather that blights you with sun-strokes and fevers. On our return to the earth we must organize a company to run regular interplanetary lines. We could start on this globe all that is best on our own. Think what boundless possibilities may be before the human race on this planet, which on account of its vast size will be in its prime when our insignificant earth is cold and dead and no longer capable of supporting life! Think also of the indescribable blessing to the congested communities of Europe and America, to find an unlimited outlet here! Mars is already past its prime, and Venus scarcely habitable, but in Jupiter we have a new promised land, compared with which our earth is a pygmy, or but little more than microscopic.”
”I see,” said Ayrault, ”that the possibilities here have no limit; but I do not see how you can compare it to the promised land, since, till we undertook this journey, no one had even thought of Jupiter as a habitable place.”
”I trace the Divine promise,” replied Bearwarden, ”in what you described to us on earth as man's innate longing and desire to rise, and in the fact that the Almighty has given the race unbounded expansiveness in very limited s.p.a.ce. This would look to me as the return of man to the garden of Eden through intellectual development, for here every man can sit under his own vine and fig-tree.”
”It seems to me,” said Cortlandt, ”that no paradise or heaven described in anything but the Bible compares with this. According to Virgil's description, the joys on the banks of his river Lethe must have been most sad and dreary, the general idleness and monotony apparently being broken only by wrestling matches between the children, while the rest strolled about with laurel wreaths or rested in the shade. The pilot Palinurus, who had been drowned by falling overboard while asleep, but who before that had presumably done his duty, did not seem especially happy; while the harsh, resentful disposition evidently remained unsoftened, for Dido became like a cliff of Marpesian marble when AEneas asked to be forgiven, though he had doubtless considered himself in duty bound to leave her, having been twice commanded to do so by Mercury, the messenger of Jove. She, like the rest, seems to have had no occupation, while the consciences of few appear to have been sufficiently clear to enable them to enjoy unbroken rest.”
”The idleness in the spirit-land of all profane writers,” added Bearwarden, ”has often surprised me too. Though I have always recommended a certain amount of recreation for my staff--in fact, more than I have generally had myself--an excess of it becomes a bore. I think that all real progress comes through thorough work. Why should we a.s.sume that progress ceases at death? I believe in the verse that says, 'We learn here on earth those things the knowledge of which is perfected in heaven.'”
”According to that,” said Cortlandt, ”you will some day be setting the axis of heaven right, for in order to do work there must be work to be done--a necessary corollary to which is that heaven is still imperfect.”
”No,” said Bearwarden, bristling up at the way Cortlandt sometimes received his speeches, ”it means simply that its development, though perfect so far as it goes, may not be finished, and that we may be the means, as on earth, of helping it along.”
”The conditions const.i.tuting heaven,” said Ayrault, ”may be as fixed as the laws of Nature, though the products of those conditions might, it seems to me, still be forming and subject to modification thereby. The reductio ad absurdu would of course apply if we supposed the work of creation absolutely finished.”
CHAPTER XIII.
NORTH-POLAR DISCOVERIES.
Two days later, on the western horizon, they beheld the ocean. Many of the streams whose sources they had seen when they crossed the divide from the lake basin, and whose courses they had followed, were now rivers a mile wide, with the tide ebbing and rising within them many hundreds of miles from their mouths. When they reached the sh.o.r.e line they found the waves breaking, as on earth, upon the sands, but with this difference: they had before noted the smallness of the undulations compared with the strength of the wind, the result of the water's weight. These waves now reminded them of the behaviour of mercury, or of melted lead when stirred on earth, by the rapidity with which the crests dropped. Though the wind was blowing an on-sh.o.r.e gale, there was but little combing, and when there was any it lasted but a second.
The one effort of the crests and waves seemed to be to remain at rest, or, if stirred in spite of themselves, to subside.
When over the surface of the ocean, the voyagers rose to a height of thirty thousand metres, and after twenty-four hours' travelling saw, at a distance of about two hundred miles, what looked like another continent, but which they knew must be an island. On finding themselves above it, they rose still higher to obtain a view of its outlines and compare its shape with that of the islands in the photographs they had had time to develop. The length ran from southeast to northwest. Though crossed by lat.i.tude forty, and notwithstanding Jupiter's distance from the sun, the southern side had a very luxuriant vegetation that was almost semi-tropical. This they accounted for by its total immunity from cold, the density of the air at sea-level, and the warm moist breezes it received from the tepid ocean. The climate was about the same as that of the Riviera or of Florida in winter, and there was, of course, no parching summer.
”This shows me,” said Bearwarden, ”that a country's climate depends less on the amount of heat it receives from the sun than on the amount it retains; proof of which we have in the tops of the Himalayas perpetually covered with snow, and snow-capped mountains on the very equator, where they get the most direct rays, and where those rays have but little air to penetrate. It shows that the presence of a substantial atmosphere is as necessary a part of the calculation in practice as the sun itself. I am inclined to think that, with the constant effect of the internal heat on its oceans and atmosphere, Jupiter could get along with a good deal less solar heat than it receives, in proof of which I expect to find the poles themselves quite comfortable. The reason the internal heat is so little taken into account on earth is because, from the thickness of the crust, it cannot make itself felt; for if the earth were as chilled through as ice, the people on the surface would not feel the difference.”
A Jovian week's explorations disclosed the fact that though the island's general outlines were fairly regular, it had deep-water harbours, great rivers, and land-locked gulfs and bays, some of which penetrated many hundred miles into the interior. It also showed that the island's length was about six thousand miles, and its breadth about three thousand, and that it had therefore about the superficial area of Asia. They found no trace of the great monsters that had been so numerous on the mainland, though there were plenty of smaller and gentle-looking creatures, among them animals whose build was much like that of the prehistoric horse, with undeveloped toes on each side of the hoof, which in the modern terrestrial horse have disappeared, the hoof being in reality but a rounded-off middle finger.
”It is wonderful,” said Bearwarden, ”how comparatively narrow a body of water can keep different species entirely separate. The island of Sumatra, for instance, is inhabited by marsupials belonging to the distinct Australian type, in which the female, as in the kangaroo, carries the slightly developed young in a pouch; while the Malay peninsula, joined to the mainland, has all the highly developed animals of Asia and the connected land of the Eastern hemisphere, the narrow Malacca Strait being all that has kept marsupials and mammals apart, though the separating power has been increased by the rapid current setting through. This has decreased the chance of creatures carried to sea on drift-wood or uprooted trees getting safely over to such a degree that apparently none have survived; for, had they done so, we may be certain that the mammals, with the advantage their young have over the marsupials, would soon have run them out, the marsupials being the older and the less perfect form of life of the two.”
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