general law, and it must have taken several successive
eruptions to form it, for the volume of its cavity is double that of its
inclosure.

All these hypotheses were allowable to terrestrial observers whose
instruments were incomplete; but Barbicane was no longer contented to
accept them, and seeing that his projectile drew regularly nearer the
lunar disc he did not despair of ultimately reaching it, or at least of
finding out the secrets of its formation.

CHAPTER XIII.

LUNAR LANDSCAPES.

At half-past two in the morning the bullet was over the 30th lunar
parallel at an effective distance of 1,000 kilometres, reduced by the
optical instruments to ten. It still seemed impossible that it could
reach any point on the disc. Its movement of translation, relatively
slow, was inexplicable to President Barbicane. At that distance from the
moon it ought to have been fast in order to maintain it against the
power of attraction. The reason of that phenomenon was also
inexplicable; besides, time was wanting to seek for the cause. The
reliefs on the lunar surface flew beneath their eyes, and they did not
want to lose a single detail.

The disc appeared through the telescopes at a distance of two and a half
leagues. If an aeronaut were taken up that distance from the earth, what
would he distinguish upon its surface? No one can tell, as the highest
ascensions have not exceeded 8,000 metres.

The following, however, is an exact description of what Barbicane and
his companions saw from that height:--

Large patches of different colours appeared on the disc. Selenographers
do not agree about their nature. They are quite distinct from each
other. Julius Schmidt is of opinion that if the terrestrial oceans were
dried up, a Selenite observer could only tell the difference between the
terrestrial oceans and continental plains by patches of colour as
distinctly varied as those which a terrestrial observer sees upon the
moon. According to him, the colour common to the vast plains, known
under the name of "seas," is dark grey, intermingled with green and
brown. Some of the large craters are coloured in the same way.

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