it a makeshift, put forward in the absence of definite knowledge, the idea being apparently that the weight of very large creatures would be too great for their strength. Of the fact that mastodons and creatures far larger than any now living on earth existed there, we have absolute proof, though gravitation must have been practically the same then as now."
Just here they came upon a number of huge bones, evidently the remains of some saurian, and many times the size of a grown crocodile. On passing a growth of most luxuriant vegetation, they saw a half-dozen sacklike objects, and drawing nearer noticed that the tops began to swell, and at the same time became lighter in colour. Just as the doctor was about to investigate one of them with his duck-shot, the enormously inflated tops of the creatures collapsed with a loud report, and the entire group soared away. When about to alight, forty yards off, they distended membranous folds in the manner of wings, which checked their descent, and on touching the ground remained where they were without rebound.
"We expected to find all kinds of reptiles and birds," exclaimed the doctor. "But I do not know how we should class those creatures. They seem to have pneumatic feet and legs, for their motion was certainly not produced like that of frogs."
When the party came up with them the heads again began to swell.
"I will perforate the air-chamber of one," said Col. Bearwarden, withdrawing the explosive cartridge from the barrel of his rifle and substituting one with a solid ball. "This will doubtless disable one so that we can examine it."
Just as they were about to rise, he shot the largest through the neck. All but the wounded one, soared off, while Bearwarden, Ayrault, and Cortlandt approached to examine it more closely.
"You see," said Cortlandt, "this vertebrate--for that is as definitely as we can yet describe it--forces a great pressure of air into its head and neck, which, by the action of valves, it must allow to rush into its very rudimentary lower extremities, distending them with such violence that the body is shot upward and forward. You may have noticed the tightly inflated portion underneath as they left the ground."
While speaking he had moved rather near, when suddenly a partially concealed mouth opened, showing the unmistakable tongue and fangs of a serpent. It emitted a hissing sound, and the small eyes gleamed maliciously.
"Do you believe it is a poisonous species?" asked Ayrault.
"I suspect it is," replied the doctor; "for, though it is doubtless able to leap with great accuracy upon its prey, we saw it took some time to recharge the upper air-chamber, so that, were it not armed with poison glands, it would fall an easy victim to its more powerful and swifter contemporaries, and would soon become extinct."
"As it will be unable to spring for some time," said Bearwarden, "we might as well save it the disappointment of trying," and, snapping the used shell from his rifle, he fired an explosive ball into the reptile, whereupon about half the body disappeared, while a sickening odour arose. Although the sun was still far above the horizon, the rapidity with which it was descending showed that the short night of less than five hours would soon be upon them; and though short it might be very dark, for they were in the tropics, and the sun, going down perpendicularly, must also pass completely around the globe, instead of, as in northern latitudes on earth in summer, approaching the horizon obliquely, and not going far below it. A slight and diffused sound here seemed to rise from the ground all about them, for which they could not account. Presently it became louder, and as the sun touched the horizon, it poured forth in prolonged strains. The large trumpet-shaped lilies, reeds, and heliotropes seemed fairly to throb as they raised their anthem to the sky and the setting sun, while the air grew dark with clouds of birds that gradually alighted on the ground, until, as the chorus grew fainter and gradually ceased, they flew back to their nests. The three companions had stood astonished while this act was played. The doctor then spoke:
"This is the most marvellous development of Nature I have seen, for its wonderful divergence from, and yet analogy to, what takes place on earth. You know our flowers offer honey, as it were, as bait to insects, that in eating or collecting it they may catch the pollen on their legs and so carry it to other flowers, perhaps of the opposite sex. Here flowers evidently appeal to the sense of hearing instead of taste, and make use of birds, of which there are enormous numbers, instead of winged insects, of which I have seen none, one being perhaps the natural result of the other. The flowers have become singers by long practice, or else, those that were most musical having had the best chance to reproduce, we have a neat illustration of the 'survival of the fittest.' The sound is doubtless produced by a shrinking of the fibres as the sun withdraws its heat, in which case we may expect another song at sunrise, when the same result will be effected by their expanding."
Searching for a camping-place in which to pass the coming hours, they saw lights flitting about like will-o'-the-wisps, but brighter and intermittent.
"They seem to be as bright as sixteen-candle-power lamps, but the light is yellower, and appears to emanate from a comparatively large surface, certainly nine or ten inches square," said the doctor.
They soon gave up the chase, however, for the lights were continually moving and frequently went out. While groping in the growing darkness, they came upon a brown object about the size of a small dog and close to the ground. It flew off with a humming insect sound, and as it did so it showed the brilliant phosphorescent glow they had observed.
"That is a good-sized fire-fly," said Bearwarden. "Evidently the insects here are on the same scale as everything else. They are like the fire-flies in Cuba, which the Cubans are said to put into a glass box and get light enough from to read by. Here they would need only one, if it could be induced to give its light continuously."
Having found an open space on high ground, they sat down, and Bearwarden struck his repeater, which, for convenience, had been arranged for Jupiter time, dividing the day into ten hours, beginning at noon, midnight being therefore five o'clock.
"Twenty minutes past four," said he, "which would correspond to about a quarter to eleven on earth. As the sun rises at half-past seven, it will be dark about three hours, for the time between dawn and daylight will, of course, be as short as that we have just experienced between sunset and night."
"If we stay here long," said the doctor, "I suppose we shall become accustomed, like sailors, to taking our four, or in this case five, hours on duty, and five hours off."
"Or," added Ayrault, "we can sleep ten consecutive hours and take the next ten for exploring and hunting, having the sun for one half the time and the moons for the other."
Bearwarden and Cortlandt now rolled themselves in their blankets and were soon asleep, while Ayrault, whose turn it was to watch till the moons rose--for they had not yet enough confidence in their new domain to sleep in darkness simultaneously--leaned his back against a rock and lighted his pipe. In the distance he saw the torrents of fiery lava from the volcanoes reflected in the sky, and faintly heard their thunderous crashes, while the fire-flies twinkled unconcernedly in the hollow, and the night winds swayed the fernlike branches. Then he gazed at the earth, which, but little above the horizon, shone with a faint but steady ray, and his mind's eye ran beyond his natural vision while he pictured to himself the girl of his heart, wishing that by some communion of spirits he might convey his thoughts to her, and receive hers. It was now the first week of January on earth. He could almost see her house and the snow-clad trees in the park, and knew that at that hour she was dressing for dinner, and hoped and believed that he was in her heart. While he thus mused, one moon after another rose, each at a different phase, till three were at once in the sky. Adjusting the electric protection-wires that were to paralyze any creature that attempted to come within the circle, and would arouse them by ringing a bell, he knocked the ashes from his pipe, rolled himself in a blanket, and was soon asleep beside his friends.
