The terrestrial atmosphere would have to be one hundred and seventy times more transparent than it is, to allow astronomers to make perfect observations on the moon's surface; but in the void in which the projectile floated no fluid interposed itself between the eye of the observer and the object observed. And more, Barbicane found himself carried to a greater distance than the most powerful telescopes had ever done before, either that of Lord Rosse or that of the Rocky Mountains. He was, therefore, under extremely favorable conditions for solving that great question of the habitability of the moon; but the solution still escaped him; he could distinguish nothing but desert beds, immense plains, and toward the north, arid mountains. Not a work betrayed the hand of man; not a ruin marked his course; not a group of animals was to be seen indicating life, even in an inferior degree. In no part was there life, in no part was there an appearance of vegetation. Of the three kingdoms which share the terrestrial globe between them, one alone was represented on the lunar and that the mineral.
"Ah, indeed!" said Michel Ardan, a little out of countenance; "then you see no one?"
"No," answered Nicholl; "up to this time, not a man, not an animal, not a tree! After all, whether the atmosphere has taken refuge at the bottom of cavities, in the midst of the circles, or even on the opposite face of the moon, we cannot decide."
"Besides," added Barbicane, "even to the most piercing eye a man cannot be distinguished farther than three and a half miles off; so that, if there are any Selenites, they can see our projectile, but we cannot see them."
Toward four in the morning, at the height of the fiftieth parallel, the distance was reduced to 300 miles. To the left ran a line of mountains capriciously shaped, lying in the full light. To the right, on the contrary, lay a black hollow resembling a vast well, unfathomable and gloomy, drilled into the lunar soil.
This hole was the "Black Lake"; it was Pluto, a deep circle which can be conveniently studied from the earth, between the last quarter and the new moon, when the shadows fall from west to east.
This black color is rarely met with on the surface of the satellite. As yet it has only been recognized in the depths of the circle of Endymion, to the east of the "Cold Sea," in the northern hemisphere, and at the bottom of Grimaldi's circle, on the equator, toward the eastern border of the orb.
Pluto is an annular mountain, situated in 51@ north latitude, and 9@ east longitude. Its circuit is forty-seven miles long and thirty-two broad.
Barbicane regretted that they were not passing directly above this vast opening. There was an abyss to fathom, perhaps some mysterious phenomenon to surprise; but the projectile's course could not be altered. They must rigidly submit. They could not guide a balloon, still less a projectile, when once enclosed within its walls. Toward five in the morning the northern limits of the "Sea of Rains" was at length passed. The mounts of Condamine and Fontenelle remained-- one on the right, the other on the left. That part of the disc beginning with 60@ was becoming quite mountainous. The glasses brought them to within two miles, less than that separating the summit of Mont Blanc from the level of the sea. The whole region was bristling with spikes and circles. Toward the 60@ Philolaus stood predominant at a height of 5,550 feet with its elliptical crater, and seen from this distance, the disc showed a very fantastical appearance. Landscapes were presented to the eye under very different conditions from those on the earth, and also very inferior to them.
The moon having no atmosphere, the consequences arising from the absence of this gaseous envelope have already been shown. No twilight on her surface; night following day and day following night with the suddenness of a lamp which is extinguished or lighted amid profound darkness-- no transition from cold to heat, the temperature falling in an instant from boiling point to the cold of space.