For a little while the travellers indulged the fond hope that they were directly approaching it, but, to their great disappointment, the path described by the Projectile lay in a different direction.

Its nature therefore they had no opportunity of ascertaining.

It began to disappear behind the dark horizon within less than half an hour after the time that M'Nicholl had signalled it.

Still, the fact of the uncontested existence of such a phenomenon was a grand one, and of considerable importance in selenographic investigations.

It proved that heat had not altogether disappeared from the lunar world; and the existence of heat once settled, who can say positively that the vegetable kingdom and even the animal kingdom have not likewise resisted so far every influence tending to destroy them?
If terrestrial astronomers could only be convinced, by undoubted evidence, of the existence of this active volcano on the Moon's surface, they would certainly admit of very considerable modifications in the present doubts regarding her inhabitability.
Thoughts of this kind continued to occupy the minds of our travellers even for some time after the little spark of light had been extinguished in the black gloom.