Photography itself could never represent what this incomparable mountain, with all its projections converging to it and its interior excrescences, is really like.  In fact, it is during the full moon that Tycho is seen in all its splendour.  Then all shadows disappear, the foreshortenings of perspective disappear, and all proofs come out white—­an unfortunate circumstance, for this strange region would have been curious to reproduce with photographic exactitude.  It is only an agglomeration of holes, craters, circles, a vertiginous network of crests.  It will be understood, therefore, that the bubblings of this central eruption have kept their first forms.  Crystallised by cooling, they have stereotyped the aspect which the moon formerly presented under the influence of Plutonic forces.

The distance which separated the travellers from the circular summits of Tycho was not so great that the travellers could not survey its principal details.  Even upon the embankment which forms the ramparts of Tycho, the mountains hanging to the interior and exterior slopes rose in stories like gigantic terraces.  They appeared to be higher by 300 or 400 feet on the west than on the east.  No system of terrestrial castrametation could equal these natural fortifications.  A town built at the bottom of this circular cavity would have been utterly inaccessible.

Inaccessible and marvellously extended over this ground of picturesque relief!  Nature had not left the bottom of this crater flat and empty.  It possessed a special orography, a mountain system which made it a world apart.  The travellers clearly distinguished the cones, central hills, remarkable movements of the ground, naturally disposed for the reception of masterpieces of Selenite architecture.  There was the place for a temple, here for a forum, there the foundations of a palace, there the plateau of a citadel, the whole overlooked by a central mountain 1,500 feet high—­a vast circuit which would have held ancient Rome ten times over.

“Ah!” exclaimed Michel Ardan, made enthusiastic by the sight, “what grand towns could be built in this circle of mountains!  A tranquil city, a peaceful refuge, away from all human cares!  How all misanthropes could live there, all haters of humanity, all those disgusted with social life!”

“All!  It would be too small for them!” replied Barbicane simply.

CHAPTER XVIII.

GRAVE QUESTIONS.

In the meantime the projectile had passed the neighbourhood of Tycho.  Barbicane and his two friends then observed, with the most scrupulous attention, those brilliant radii which the celebrated mountain disperses so curiously on every horizon.