It would seem that the Selenites who came upon him carried him to some point in the interior down "a great shaft" by means of what he describes as "a sort of balloon." We gather from the rather confused passage in which he describes this, and from a number of chance allusions and hints in other and subsequent messages, that this "great shaft" is one of an enormous system of artificial shafts that run, each from what is called a lunar "crater" downwards for very nearly a hundred miles towards the central portion of our satellite. These shafts communicate by transverse tunnels, they throw out abysmal caverns and expand into great globular places; the whole of the moon's substance for a hundred miles inward, indeed, is a mere sponge of rock. "Partly," says Cavor, "this sponginess is natural, but very largely it is due to the enormous industry of the Selenites in the past. The great circular mounds of the excavated rock and earth that form these great circles about the tunnels are known to earthly astronomers (misled by a false analogy) as volcanoes."
It was down this shaft they took him, in this "sort of balloon" he speaks of, at first into an inky blackness and then into a region of continually increasing phosphorescence. Cavor's despatches show him to be, for a scientific man, curiously regardless of detail, but we gather that this light was due to the streams and cascades of water—"no doubt containing some phosphorescent organism"—that flowed ever more abundantly downward towards the Central Sea. And as he descended, he says: "The Sele-
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