Lecouturier and Chapuis, a fine model set up in 1860, of very correct design and clear outlines. Such is the nomenclature of the different maps relating to the lunar world. Barbicane possessed two, that of Messrs. Boeer and Moedler and that of Messrs. Chapuis and Lecouturier. They were to make his work of observer easier. They had excellent marine glasses specially constructed for this journey.

Such is the reason for the apparent reversal of these two cardinal points, and this must be remembered whilst following the observations of President Barbicane. Helped by the Mappa Selenographica of Boeer and Moedler, the travellers could, without hesitating, survey that portion of the disc in the field of their telescopes. "What are we looking at now?" asked Michel.

Boeer and Moedler measured 1,905 different elevations, of which six exceed 15,000 feet and twenty-two exceed 14,400 feet. Their highest summit towers to a height of 22,606 feet above the surface of the lunar disc. At the same time the survey of the moon was being completed; she appeared riddled with craters, and her essentially volcanic nature was affirmed by each observation.

The selenographic maps make it the lower one, because they are generally drawn up according to the image given by the telescopes, and we know that they reverse the objects. Such was the Mappa Selenographica of Boeer and Moedler which Barbicane consulted. This northern hemisphere presented vast plains, relieved by isolated mountains. At midnight the moon was full.

Some of the large craters present the same appearance. Barbicane knew this opinion of the German selenographer, an opinion shared by Boeer and Moedler. Observation has proved that right was on their side, and not on that of some astronomers who admit the existence of only gray on the moon's surface.

The travellers were desirous of examining the moon during their transit, and in order to facilitate the survey of this new world they took an excellent map by Boeer and Moedler, the Mappa Selenographica, published in four plates, which is justly looked upon as a masterpiece of patience and observation.

The earliest observations did not discover these furrows. Neither Hevelius, Cassini, La Hire, nor Herschel seems to have known them. It was Schroeter who in 1789 first attracted the attention of savants to them. Others followed who studied them, such as Pastorff, Gruithuysen, Boeer, and Moedler.

These natural accidents naturally excited the imaginations of these terrestrial astronomers. The first observations had not discovered these rifts. Neither Hevelius, Cassin, La Hire, nor Herschel seemed to have known them. It was Schroeter who in 1789 first drew attention to them. Others followed who studied them, as Pastorff, Gruithuysen, Boeer, and Moedler.

Hevelius singularly reduced these figures, which Riccioli, on the contrary, doubled. All these measures were exaggerated. Herschel, with his more perfect instruments, approached nearer the hypsometric truth. But it must be finally sought in the accounts of modern observers. Messrs. Boeer and Moedler, the most perfect selenographers in the whole world, have measured 1,095 lunar mountains.

"Yes, sir; and I may add that the most skilful observers, MM. Boeer and Moedler, agree that air is absolutely wanting on the moon's surface." A movement took place amongst the audience, who appeared struck by the arguments of this singular personage. "We will pass on again," answered Michel Ardan, with the greatest calmness, "and arrive now at an important fact.