"Now," he said, "it seems such an obvious thing."
"Of course! The moon must be enormously cavernous, with an atmosphere within, and at the centre of its caverns a sea.
"One knew that the moon had a lower specific gravity than the earth, one knew that it had little air or water outside, one knew, too, that it was sister planet to the earth, and that it was unaccountable that it should be different in composition. The inference that it was hollowed out was as clear as day. And yet one never saw it as a fact. Kepler, of course———"
His voice had the interest now of a man who has discerned a pretty sequence of reasoning.
"Yes," he said, "Kepler with his sub-volvani was right after all."
"I wish you had taken the trouble to find that out before we came," I said.
He answered nothing, buzzing to himself softly, as he pursued his thoughts. My temper was going. "What do you think has become of the sphere, anyhow?" I asked.
"Lost," he said, like a man who answers an uninteresting question.
"Among those plants?"
"Unless they find it."
"And then?"
