The lunar disc being brought within a distance of about six miles by the spy-glasses, it is a fair question to ask, what could an aeronaut at such an elevation from our Earth discover on its surface? At present that question can hardly be answered, the most remarkable balloon ascensions never having passed an altitude of five miles under circumstances favorable for observers. Here, however, is an account, carefully transcribed from notes taken on the spot, of what Barbican and his companions did see from their peculiar post of observation.
Varieties of color, in the first place, appeared here and there upon the disc. Selenographers are not quite agreed as to the nature of these colors. Not that such colors are without variety or too faint to be easily distinguished. Schmidt of Athens even says that if our oceans on earth were all evaporated, an observer in the Moon would hardly find the seas and continents of our globe even so well outlined as those of the Moon are to the eye of a terrestrial observer. According to him, the shade of color distinguishing those vast plains known as "seas" is a dark gray dashed with green and brown,—a color presented also by a few of the great craters.
This opinion of Schmidt's, shared by Beer and Maedler, Barbican's observations now convinced him to be far better founded than that of certain astronomers who admit of no color at all being visible on the Moon's surface but gray. In certain spots the greenish tint was quite decided, particularly in Mare Serenitatis and Mare Humorum, the very localities where Schmidt had most noticed it. Barbican also remarked that several large craters, of the class that had no interior cones, reflected a kind of bluish tinge, somewhat like that given forth by a freshly polished steel plate. These tints, he now saw enough to convince him, proceeded really from the lunar surface, and were not due, as certain astronomers asserted, either to the imperfections of the spy-glasses, or to the interference of the terrestrial atmosphere. His singular opportunity for correct observation allowed him to entertain no doubt whatever on the subject. Hampered by no atmosphere, he was free from all liability to optical illusion. Satisfied therefore as to the reality of these tints, he considered such knowledge a positive gain to science. But that greenish tint—to what was it due? To a dense tropical vegetation maintained by a low atmosphere, a mile or so in thickness? Possibly. But this was another question that could not be answered at present.
Further on he could detect here and there traces of a decidedly ruddy tint. Such a shade he knew had been already detected in the Palus Somnii, near Mare Crisium, and in the circular area of Lichtenberg, near the Hercynian Mountains, on the eastern edge of the Moon. To what cause was this tint to be attributed? To the actual color of the surface itself? Or to that of the lava covering it here and there? Or to the color resulting from the mixture of other colors seen at a distance too great to allow of their being distinguished separately? Impossible to tell.
Barbican and his companions succeeded no better at a new problem that soon engaged their undivided attention. It deserves some detail.
Having passed Lambert, being just over Timocharis, all were attentively gazing at the magnificent crater of Archimedes with a diameter of 52 miles across and ramparts more than 5000 feet in height, when Ardan startled his companions by suddenly exclaiming:
"Hello! Cultivated fields as I am a living man!"
"What do you mean by your cultivated fields?" asked M'Nicholl sourly, wiping his glasses and shrugging his shoulders.
"Certainly cultivated fields!" replied Ardan. "Don't you see the furrows? They're certainly plain enough. They are white too from glistening in the sun, but they are quite different from the radiating streaks of Copernicus. Why, their sides are perfectly parallel!"
"Where are those furrows?" asked M'Nicholl, putting his glasses to his eye and adjusting the focus.