"Friend Ardan," interposed Barbican, who noticed that the Captain was a little too disconcerted to give a ready reply; "Friend Ardan, I must say you are not quite wrong in showing how certain methods of reasoning, legitimate enough in themselves, may be easily abused by being carried too far. I think, however, that the Captain might maintain his position without having recourse to speculations altogether too gigantic for ordinary intellect. By simply admitting the insufficiency of the primordeal attraction to preserve a perfect balance between the movements of the lunar rotation and revolution, we can easily see how the nights and days could once succeed each other on the Moon exactly as they do at present on the Earth."

"Nothing can be clearer!" resumed the brave Captain, once more rushing to the charge. "Besides, even without this alternation of days and nights, life on the lunar surface was quite possible."

"Of course it was possible," said Ardan; "everything is possible except what contradicts itself. It is possible too that every possibility is a fact; therefore, it _is_ a fact. However," he added, not wishing to press the Captain's weak points too closely, "let all these logical niceties pa.s.s for the present. Now that you have established the existence of your humanity in the Moon, the Chair would respectfully ask how it has all so completely disappeared?"

"It disappeared completely thousands, perhaps millions, of years ago,"

replied the unabashed Captain. "It perished from the physical impossibility of living any longer in a world where the atmosphere had become by degrees too rare to be able to perform its functions as the great resuscitating medium of dependent existences. What took place on the Moon is only what is to take place some day or other on the Earth, when it is sufficiently cooled off."

"Cooled off?"

"Yes," replied the Captain as confidently and with as little hesitation as if he was explaining some of the details of his great machine-shop in Philadelphia; "You see, according as the internal fire near the surface was extinguished or was withdrawn towards the centre, the lunar sh.e.l.l naturally cooled off. The logical consequences, of course, then gradually took place: extinction of organized beings; and then extinction of vegetation. The atmosphere, in the meantime, became thinner and thinner--partly drawn off with the water evaporated by the terrestrial attraction, and partly sinking with the solid water into the crust-cracks caused by cooling. With the disappearance of air capable of respiration, and of water capable of motion, the Moon, of course, became uninhabitable. From that day it became the abode of death, as completely as it is at the present moment."

"That is the fate in store for our Earth?"

"In all probability."

"And when is it to befall us?"

"Just as soon as the crust becomes cold enough to be uninhabitable."

"Perhaps your philosophership has taken the trouble to calculate how many years it will take our unfortunate _Terra Mater_ to cool off?"

"Well; I have."

"And you can rely on your figures?"

"Implicitly."

"Why not tell it at once then to a fellow that's dying of impatience to know all about it? Captain, the Chair considers you one of the most tantalizing creatures in existence!"

"If you only listen, you will hear," replied M'Nicholl quietly. "By careful observations, extended through a series of many years, men have been able to discover the average loss of temperature endured by the Earth in a century. Taking this as the ground work of their calculations, they have ascertained that our Earth shall become an uninhabitable planet in about--"

"Don't cut her life too short! Be merciful!" cried Ardan in a pleading tone half in earnest. "Come, a good long day, your Honor! A good long day!"

"The planet that we call the Earth," continued the Captain, as grave as a judge, "will become uninhabitable to human beings, after a lapse of 400 thousand years from the present time."

"Hurrah!" cried Ardan, much relieved. "_Vive la Science!_ Henceforward, what miscreant will persist in saying that the Savants are good for nothing? Proudly pointing to this calculation, can't they exclaim to all defamers: 'Silence, croakers! Our services are invaluable! Haven't we insured the Earth for 400 thousand years?' Again I say _vive la Science!_"

"Ardan," began the Captain with some asperity, "the foundations on which Science has raised--"

"I'm half converted already," interrupted Ardan in a cheery tone; "I do really believe that Science is not altogether unmitigated homebogue!

_Vive_--"

--"But what has all this to do with the question under discussion?"

interrupted Barbican, desirous to keep his friends from losing their tempers in idle disputation.

"True!" said Ardan. "The Chair, thankful for being called to order, would respectfully remind the house that the question before it is: _Has the Moon been inhabited?_ Affirmative has been heard. Negative is called on to reply. Mr. Barbican has the _parole_."

But Mr. Barbican was unwilling just then to enter too deeply into such an exceedingly difficult subject. "The probabilities," he contented himself with saying, "would appear to be in favor of the Captain's speculations. But we must never forget that they _are_ speculations--nothing more. Not the slightest evidence has yet been produced that the Moon is anything else than 'a dead and useless waste of extinct volcanoes.' No signs of cities, no signs of buildings, not even of ruins, none of anything that could be reasonably ascribed to the labors of intelligent creatures. No sign of change of any kind has been established. As for the agreement between the Moon's rotation and her revolution, which compels her to keep the same face constantly turned towards the Earth, we don't know that it has not existed from the beginning. As for what is called the effect of volcanic agency upon her surface, we don't know that her peculiar blistered appearance may not have been brought about altogether by the bubbling and spitting that blisters molten iron when cooling and contracting. Some close observers have even ventured to account for her craters by saying they were due to pelting showers of meteoric rain. Then again as to her atmosphere--why should she have lost her atmosphere? Why should it sink into craters?

Atmosphere is gas, great in volume, small in matter; where would there be room for it? Solidified by the intense cold? Possibly in the night time. But would not the heat of the long day be great enough to thaw it back again? The same trouble attends the alleged disappearance of the water. Swallowed up in the cavernous cracks, it is said. But why are there cracks? Cooling is not always attended by cracking. Water cools without cracking; cannon b.a.l.l.s cool without cracking. Too much stress has been laid on the great difference between the _nucleus_ and the _crust_: it is really impossible to say where one ends and the other begins. In fact, no theory explains satisfactorily anything regarding the present state of the Moon's surface. In fact, from the day that Galileo compared her cl.u.s.tering craters to 'eyes on a peac.o.c.k's tail' to the present time, we must acknowledge that we know nothing more than we can actually see, not one particle more of the Moon's history than our telescopes reveal to our corporal eyes!"

"In the lucid opinion of the honorable and learned gentleman who spoke last," said Ardan, "the Chair is compelled to concur. Therefore, as to the second question before the house for deliberation, _Has the Moon been ever inhabited?_ the Chair gets out of its difficulty, as a Scotch jury does when it has not evidence enough either way, by returning a solemn verdict of _Not Proven!_"

"And with this conclusion," said Barbican, hastily rising, "of a subject on which, to tell the truth, we are unable as yet to throw any light worth speaking of, let us be satisfied for the present. Another question of greater moment to us just now is: where are we? It seems to me that we are increasing our distance from the Moon very decidedly and very rapidly."

It was easy to see that he was quite right in this observation. The Projectile, still following a northerly course and therefore approaching the lunar equator, was certainly getting farther and farther from the Moon. Even at 30 S., only ten degrees farther north than the lat.i.tude of _Tycho_, the travellers had considerable difficulty, comparatively, in observing the details of _Pitatus_, a walled mountain on the south sh.o.r.es of the _Mare Nubium_. In the "sea" itself, over which they now floated, they could see very little, but far to the left, on the 20th parallel, they could discern the vast crater of _Bullialdus_, 9,000 feet deep. On the right, they had just caught a glimpse of _Purbach_, a depressed valley almost square in shape with a round crater in the centre, when Ardan suddenly cried out:

"A Railroad!"

And, sure enough, right under them, a little northeast of _Purbach_, the travellers easily distinguished a long line straight and black, really not unlike a railroad cutting through a low hilly country.

This, Barbican explained, was of course no railway, but a steep cliff, at least 1,000 feet high, casting a very deep shadow, and probably the result of the caving in of the surface on the eastern edge.

Then they saw the immense crater of _Arzachel_ and in its midst a cone mountain shining with dazzling splendor. A little north of this, they could detect the outlines of another crater, _Alphonse_, at least 70 miles in diameter. Close to it they could easily distinguish the immense crater or, as some observers call it, Ramparted Plain, _Ptolemy_, so well known to lunar astronomers, occupying, as it does, such a favorable position near the centre of the Moon, and having a diameter fully, in one direction at least, 120 miles long.

The travellers were now in about the same lat.i.tude as that at which they had at first approached the Moon, and it was here that they began most unquestionably to leave her. They looked and looked, readjusting their gla.s.ses, but the details were becoming more and more difficult to catch.

The reliefs grew more and more blurred and the outlines dimmer and dimmer. Even the great mountain profiles began to fade away, the dazzling colors to grow duller, the jet black shadows greyer, and the general effect mistier.

At last, the distance had become so great that, of this lunar world so wonderful, so fantastic, so weird, so mysterious, our travellers by degrees lost even the consciousness, and their sensations, lately so vivid, grew fainter and fainter, until finally they resembled those of a man who is suddenly awakened from a peculiarly strange and impressive dream.

CHAPTER XIX.

IN EVERY FIGHT, THE IMPOSSIBLE WINS.

No matter what we have been accustomed to, it is sad to bid it farewell forever. The glimpse of the Moon's wondrous world imparted to Barbican and his companions had been, like that of the Promised Land to Moses on Mount Pisgah, only a distant and a dark one, yet it was with inexpressibly mournful eyes that, silent and thoughtful, they now watched her fading away slowly from their view, the conviction impressing itself deeper and deeper in their souls that, slight as their acquaintance had been, it was never to be renewed again. All doubt on the subject was removed by the position gradually, but decidedly, a.s.sumed by the Projectile. Its base was turning away slowly and steadily from the Moon, and pointing surely and unmistakably towards the Earth.

Barbican had been long carefully noticing this modification, but without being able to explain it. That the Projectile should withdraw a long distance from the Moon and still be her satellite, he could understand; but, being her satellite, why not present towards her its heaviest segment, as the Moon does towards the Earth? That was the point which he could not readily clear up.

By carefully noting its path, he thought he could see that the Projectile, though now decidedly leaving the Moon, still followed a curve exactly a.n.a.logous to that by which it had approached her. It must therefore be describing a very elongated ellipse, which might possibly extend even to the neutral point where the lunar and terrestrial attractions were mutually overcome.

With this surmise of Barbican's, his companions appeared rather disposed to agree, though, of course, it gave rise to new questions.

"Suppose we reach this dead point," asked Ardan; "what then is to become of us?"

"Can't tell!" was Barbican's unsatisfactory reply.

"But you can form a few hypotheses?"

"Yes, two!"

"Let us have them."

"The velocity will be either sufficient to carry us past the dead point, or it will not: sufficient, we shall keep on, just as we are now, gravitating forever around the Moon--"

--"Hypothesis number two will have at least one point in its favor,"