At this point, under their feet, rose Mount Helicon, 1520 feet high, and round about the left rose moderate elevations, enclosing a small portion of the "Sea of Rains," under the name of the Gulf of Iris. 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 favourable 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 towards 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 miles and a half off; so that, if there are any Selenites, they can see our projectile, but we cannot see them." Towards 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 colour 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, towards 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.