There it lay below them, a round black spot, hiding the sweet faces of the stars, but otherwise no more distinguishable by the travellers than if they were lying in the depths of the Mammoth Cave of Kentucky. And just think. Only fifteen days before, that dark face had been splendidly illuminated by the solar beams, every crater lustrous, every peak sparkling, every streak glistening under the vertical ray. In fifteen days later, a day light the most brilliant would have replaced a midnight the most Cimmerian. But in fifteen days later, where would the Projectile be? In what direction would it have been drawn by the forces innumerable of attractions incalculable? To such a question as this, even Ardan would reply only by an ominous shake of the head. We know already that our travellers, as well as astronomers generally, judging from that portion of the dark side occasionally revealed by the Moon's librations, were _pretty certain_ that there is no great difference between her two sides, as far as regards their physical constitutions. This portion, about the seventh part, shows plains and mountains, circles and craters, all of precisely the same nature as those already laid down on the chart. Judging therefore from analogy, the other three-sevenths are, in all probability a world in every respect exactly like the visible face--that is, arid, desert, dead. But our travellers also knew that _pretty certain_ is far from _quite certain_, and that arguing merely from analogy may enable you to give a good guess, but can never lead you to an undoubted conclusion. What if the atmosphere had really withdrawn to this dark face? And if air, why not water? Would not this be enough to infuse life into the whole continent? Why should not vegetation flourish on its plains, fish in its seas, animals in its forests, and man in every one of its zones that were capable of sustaining life? To these interesting questions, what a satisfaction it would be to be able to answer positively one way or another! For thousands of difficult problems a mere glimpse at this hemisphere would be enough to furnish a satisfactory reply. How glorious it would be to contemplate a realm on which the eye of man has never yet rested! Great, therefore, as you may readily conceive, was the depression of our travellers' spirits, as they pursued their way, enveloped in a veil of darkness the most profound. Still even then Ardan, as usual, formed somewhat of an exception. Finding it impossible to see a particle of the Lunar surface, he gave it up for good, and tried to console himself by gazing at the stars, which now fairly blazed in the spangled heavens. And certainly never before had astronomer enjoyed an opportunity for gazing at the heavenly bodies under such peculiar advantages. How Fraye of Paris, Chacornac of Lyons, and Father Secchi of Rome would have envied him!