But the projectile had passed the _enceinte_ of Tycho, and Barbicane and his two companions watched with scrupulous attention the brilliant rays which the celebrated mountain shed so curiously over the horizon.
What was this radiant glory? What geological phenomenon had designed these ardent beams? This question occupied Barbicane's mind.
Under his eyes ran in all directions luminous furrows, raised at the edges and concave in the center, some twelve miles, others thirty miles broad. These brilliant trains extended in some places to within 600 miles of Tycho, and seemed to cover, particularly toward the east, the northeast and the north, the half of the southern hemisphere. One of these jets extended as far as the circle of Neander, situated on the 40th meridian. Another, by a slight curve, furrowed the "Sea of Nectar," breaking against the chain of Pyrenees, after a circuit of 800 miles. Others, toward the west, covered the "Sea of Clouds" and the "Sea of Humors" with a luminous network. What was the origin of these sparkling rays, which shone on the plains as well as on the reliefs, at whatever height they might be? All started from a common center, the crater of Tycho. They sprang from him. Herschel attributed their brilliancy to currents of lava congealed by the cold; an opinion, however, which has not been generally adopted. Other astronomers have seen in these inexplicable rays a kind of moraines, rows of erratic blocks, which had been thrown up at the period of Tycho's formation.
"And why not?" asked Nicholl of Barbicane, who was relating and rejecting these different opinions.
"Because the regularity of these luminous lines, and the violence necessary to carry volcanic matter to such distances, is inexplicable."
"Eh! by Jove!" replied Michel Ardan, "it seems easy enough to me to explain the origin of these rays."
"Indeed?" said Barbicane.
"Indeed," continued Michel. "It is enough to say that it is a vast star, similar to that produced by a ball or a stone thrown at a square of glass!"
"Well!" replied Barbicane, smiling. "And what hand would be powerful enough to throw a ball to give such a shock as that?"
"The hand is not necessary," answered Nicholl, not at all confounded; "and as to the stone, let us suppose it to be a comet."
"Ah! those much-abused comets!" exclaimed Barbicane. "My brave Michel, your explanation is not bad; but your comet is useless. The shock which produced that rent must have some from the inside of the star. A violent contraction of the lunar crust, while cooling, might suffice to imprint this gigantic star."
"A contraction! something like a lunar stomach-ache." said Michel Ardan.
"Besides," added Barbicane, "this opinion is that of an English savant, Nasmyth, and it seems to me to sufficiently explain the radiation of these mountains."
"That Nasmyth was no fool!" replied Michel.
Long did the travelers, whom such a sight could never weary, admire the splendors of Tycho. Their projectile, saturated with luminous gleams in the double irradiation of sun and moon, must have appeared like an incandescent globe. They had passed suddenly from excessive cold to intense heat. Nature was thus preparing them to become Selenites. Become Selenites! That idea brought up once more the question of the habitability of the moon. After what they had seen, could the travelers solve it? Would they decide for or against it? Michel Ardan persuaded his two friends to form an opinion, and asked them directly if they thought that men and animals were represented in the lunar world.
"I think that we can answer," said Barbicane; "but according to my idea the question ought not to be put in that form. I ask it to be put differently."
"Put it your own way," replied Michel.
"Here it is," continued Barbicane. "The problem is a double one, and requires a double solution. Is the moon _habitable_? Has the moon ever been _inhabitable_?"
"Good!" replied Nicholl. "First let us see whether the moon is habitable."
"To tell the truth, I know nothing about it," answered Michel.
"And I answer in the negative," continued Barbicane. "In her actual state, with her surrounding atmosphere certainly very much reduced, her seas for the most part dried up, her insufficient supply of water restricted, vegetation, sudden alternations of cold and heat, her days and nights of 354 hours-- the moon does not seem habitable to me, nor does she seem propitious to animal development, nor sufficient for the wants of existence as we understand it."
"Agreed," replied Nicholl. "But is not the moon habitable for creatures differently organized from ourselves?"
"That question is more difficult to answer, but I will try; and I ask Nicholl if _motion_ appears to him to be a necessary result of _life_, whatever be its organization?"
"Without a doubt!" answered Nicholl.
"Then, my worthy companion, I would answer that we have observed the lunar continent at a distance of 500 yards at most, and that nothing seemed to us to move on the moon's surface. The presence of any kind of life would have been betrayed by its attendant marks, such as divers buildings, and even by ruins. And what have we seen? Everywhere and always the geological works of nature, never the work of man. If, then, there exist representatives of the animal kingdom on the moon, they must have fled to those unfathomable cavities which the eye cannot reach; which I cannot admit, for they must have left traces of their passage on those plains which the atmosphere must cover, however slightly raised it may be. These traces are nowhere visible. There remains but one hypothesis, that of a living race to which motion, which is life, is foreign."
"One might as well say, living creatures which do not live," replied Michel.
"Just so," said Barbicane, "which for us has no meaning."
"Then we may form our opinion?" said Michel.
"Yes," replied Nicholl.
"Very well," continued Michel Ardan, "the Scientific Commission assembled in the projectile of the Gun Club, after having founded their argument on facts recently observed, decide unanimously upon the question of the habitability of the moon-- `_No!_ the moon is not habitable.'"
This decision was consigned by President Barbicane to his notebook, where the process of the sitting of the 6th of December may be seen.
"Now," said Nicholl, "let us attack the second question, an indispensable complement of the first. I ask the honorable commission, if the moon is not habitable, has she ever been inhabited, Citizen Barbicane?"
"My friends," replied Barbicane, "I did not undertake this journey in order to form an opinion on the past habitability of our satellite; but I will add that our personal observations only confirm me in this opinion. I believe, indeed I affirm, that the moon has been inhabited by a human race organized like our own; that she has produced animals anatomically formed like the terrestrial animals: but I add that these races, human and animal, have had their day, and are now forever extinct!"
"Then," asked Michel, "the moon must be older than the earth?"
"No!" said Barbicane decidedly, "but a world which has grown old quicker, and whose formation and deformation have been more rapid. Relatively, the organizing force of matter has been much more violent in the interior of the moon than in the interior of the terrestrial globe. The actual state of this cracked, twisted, and burst disc abundantly proves this. The moon and the earth were nothing but gaseous masses originally. These gases have passed into a liquid state under different influences, and the solid masses have been formed later. But most certainly our sphere was still gaseous or liquid, when the moon was solidified by cooling, and had become habitable."
"I believe it," said Nicholl.
"Then," continued Barbicane, "an atmosphere surrounded it, the waters contained within this gaseous envelope could not evaporate. Under the influence of air, water, light, solar heat, and central heat, vegetation took possession of the continents prepared to receive it, and certainly life showed itself about this period, for nature does not expend herself in vain; and a world so wonderfully formed for habitation must necessarily be inhabited."
"But," said Nicholl, "many phenomena inherent in our satellite might cramp the expansion of the animal and vegetable kingdom. For example, its days and nights of 354 hours?"
"At the terrestrial poles they last six months," said Michel.
"An argument of little value, since the poles are not inhabited."
"Let us observe, my friends," continued Barbicane, "that if in the actual state of the moon its long nights and long days created differences of temperature insupportable to organization, it was not so at the historical period of time. The atmosphere enveloped the disc with a fluid mantle; vapor deposited itself in the shape of clouds; this natural screen tempered the ardor of the solar rays, and retained the nocturnal radiation. Light, like heat, can diffuse itself in the air; hence an equality between the influences which no longer exists, now that atmosphere has almost entirely disappeared. And now I am going to astonish you."
"Astonish us?" said Michel Ardan.
"I firmly believe that at the period when the moon was inhabited, the nights and days did not last 354 hours!"
"And why?" asked Nicholl quickly.
"Because most probably then the rotary motion of the moon upon her axis was not equal to her revolution, an equality which presents each part of her disc during fifteen days to the action of the solar rays."
"Granted," replied Nicholl, "but why should not these two motions have been equal, as they are really so?"
"Because that equality has only been determined by terrestrial attraction. And who can say that this attraction was powerful enough to alter the motion of the moon at that period when the earth was still fluid?"
"Just so," replied Nicholl; "and who can say that the moon has always been a satellite of the earth?"
"And who can say," exclaimed Michel Ardan, "that the moon did not exist before the earth?"
Their imaginations carried them away into an indefinite field of hypothesis. Barbicane sought to restrain them.
"Those speculations are too high," said he; "problems utterly insoluble. Do not let us enter upon them. Let us only admit the insufficiency of the primordial attraction; and then by the inequality of the two motions of rotation and revolution, the days and nights could have succeeded each other on the moon as they succeed each other on the earth. Besides, even without these conditions, life was possible."
"And so," asked Michel Ardan, "humanity has disappeared from the moon?"
"Yes," replied Barbicane, "after having doubtless remained persistently for millions of centuries; by degrees the atmosphere becoming rarefied, the disc became uninhabitable, as the terrestrial globe will one day become by cooling."
"Certainly," replied Barbicane; "as the internal fires became extinguished, and the incandescent matter concentrated itself, the lunar crust cooled. By degrees the consequences of these phenomena showed themselves in the disappearance of organized beings, and by the disappearance of vegetation. Soon the atmosphere was rarefied, probably withdrawn by terrestrial attraction; then aerial departure of respirable air, and disappearance of water by means of evaporation. At this period the moon becoming uninhabitable, was no longer inhabited. It was a dead world, such as we see it to-day."
"And you say that the same fate is in store for the earth?"
"When the cooling of its crust shall have made it uninhabitable."
"And have they calculated the time which our unfortunate sphere will take to cool?"
"And you know these calculations?"
"But speak, then, my clumsy savant," exclaimed Michel Ardan, "for you make me boil with impatience!"
"Very well, my good Michel," replied Barbicane quietly; "we know what diminution of temperature the earth undergoes in the lapse of a century. And according to certain calculations, this mean temperature will after a period of 400,000 years, be brought down to zero!"
"Four hundred thousand years!" exclaimed Michel. "Ah! I breathe again. Really I was frightened to hear you; I imagined that we had not more than 50,000 years to live."
Barbicane and Nicholl could not help laughing at their companion's uneasiness. Then Nicholl, who wished to end the discussion, put the second question, which had just been considered again.
"Has the moon been inhabited?" he asked.
The answer was unanimously in the affirmative. But during this discussion, fruitful in somewhat hazardous theories, the projectile was rapidly leaving the moon: the lineaments faded away from the travelers' eyes, mountains were confused in the distance; and of all the wonderful, strange, and fantastical form of the earth's satellite, there soon remained nothing but the imperishable remembrance.