Barbicane knew this opinion of the German selenographer; it is shared by Messrs. Boeer and Moedler.  He noticed that they were right, whilst certain astronomers, who only allow grey colouring on the surface of the moon, are wrong.  In certain places the green colour was very vivid; according to Julius Schmidt, it is so in the Seas of Serenity and Humours.  Barbicane likewise remarked the wide craters with no interior cones, which are of a bluish colour, analogous to that of fresh-polished sheets of steel.  These colours really belonged to the lunar disc, and did not result, as certain astronomers think, either from some imperfection in the object-glasses of the telescopes or the interposition of the terrestrial atmosphere.  Barbicane had no longer any doubt about it.  He was looking at it through the void, and could not commit any optical error.  He considered that the existence of this different colouring was proved to science.  Now were the green shades owing to tropical vegetation, kept up by a low and dense atmosphere?  He could not yet be certain.

Farther on he noticed a reddish tinge, quite sufficiently distinct.  A similar colour had already been observed upon the bottom of an isolated inclosure, known under the name of the Lichtenberg Amphitheatre, which is situated near the Hercynian Mountains, on the border of the moon.  But he could not make out its nature.

He was not more fortunate about another peculiarity of the disc, for he could not find out its cause.  The peculiarity was the following one:—­

Michel Ardan was watching near the president when he remarked some long white lines brilliantly lighted up by the direct rays of the sun.  It was a succession of luminous furrows, very different from the radiation that Copernicus had presented.  They ran in parallel lines.

Michel, with his usual readiness, exclaimed—­

“Why, there are cultivated fields!”

“Cultivated fields!” repeated Nicholl, shrugging his shoulders.

“Ploughed fields, at all events,” replied Michel Ardan.  “But what ploughmen these Selenites must be, and what gigantic oxen they must harness to their ploughs, to make such furrows!”

“They are not furrows, they are crevices!”

“Crevices let them be,” answered Michel with docility.  “Only what do you mean by crevices in the world of science?” Barbicane soon told his companions all he knew about lunar crevices.  He knew that they were furrows observed upon all the non-mountainous parts of the lunar disc; that these furrows, generally isolated, were from four to five leagues only; that their width varies from 1,000 to 1,500 metres, and their edges are rigorously parallel.  But he knew nothing more about their formation or their nature.

Barbicane watched these furrows through his telescope very attentively.  He noticed that their banks were exceedingly steep.  They were long parallel ramparts; with a little imagination they might be taken for long lines of fortifications raised by Selenite engineers.