Towards five in the morning, the northern limit of _Mare Imbrium_ was finally passed, and _Mare Frigoris_ spread its frost-colored plains far to the right and left. On the east the travellers could easily see the ring-mountain _Condamine_, about 4000 feet high, while a little ahead on the right they could plainly distinguish _Fontenelle_ with an altitude nearly twice as great. _Mare Frigoris_ was soon passed, and the whole lunar surface beneath the travellers, as far as they could see in all directions, now bristled with mountains, crags, and peaks. Indeed, at the 70th parallel the "Seas" or plains seem to have come to an end. The spy-glasses now brought the surface to within about three miles, a distance less than that between the hotel at Chamouni and the summit of Mont Blanc. To the left, they had no difficulty in distinguishing the ramparts of _Philolaus_, about 12,000 feet high, but though the crater had a diameter of nearly thirty miles, the black shadows prevented the slightest sign of its interior from being seen. The Sun was now sinking very low, and the illuminated surface of the Moon was reduced to a narrow rim. By this time, too, the bird's eye view to which the observations had so far principally confined, decidedly altered its character. They could now look back at the lunar mountains that they had been just sailing over--a view somewhat like that enjoyed by a tourist standing on the summit of Mt. St. Gothard as he sees the sun setting behind the peaks of the Bernese Oberland. The lunar landscapes however, though seen under these new and ever varying conditions, "hardly gained much by the change," according to Ardan's expression. On the contrary, they looked, if possible, more dreary and inhospitable than before.