my
friend, I should indeed be mad."

I attempted to explain the force of gravity to him, and by the means of
the dropped fruit to illustrate how impossible it would be for a body
to fall off the earth under any circumstances. He listened so intently
that I thought I had made an impression, and started the train of
thought that would lead him to a partial understanding of the truth.
But I was mistaken.

"Your own illustration," he said finally, "proves the falsity of your
theory." He dropped a fruit from his hand to the ground. "See," he
said, "without support even this tiny fruit falls until it strikes
something that stops it. If Pellucidar were not supported upon the
flaming sea it too would fall as the fruit falls--you have proven it
yourself!" He had me, that time--you could see it in his eye.

It seemed a hopeless job and I gave it up, temporarily at least, for
when I contemplated the necessity explanation of our solar system and
the universe I realized how futile it would be to attempt to picture to
Ja or any other Pellucidarian the sun, the moon, the planets, and the
countless stars. Those born within the inner world could no more
conceive of such things than can we of the outer crust reduce to
factors appreciable to our finite minds such terms as space and
eternity.

"Well, Ja," I laughed, "whether we be walking with our feet up or down,
here we are, and the question of greatest importance is not so much
where we came from as where we are going now. For my part I wish that
you could guide me to Phutra where I may give myself up to the Mahars
once more that my friends and I may work out the plan of escape which
the Sagoths interrupted when they gathered us together and drove us to
the arena to witness the punishment of the slaves who killed the
guardsman. I wish now that I had not left the arena for by this time
my friends and I might have made good our escape, whereas this delay
may mean the wrecking of all our plans, which depended for their
consummation upon the continued sleep of the three Mahars who lay in
the pit beneath the building in which we were confined."

"You would return to captivity?" cried Ja.

"My friends are there," I replied, "the only friends I have in
Pellucidar, except yourself. What else may I do under the
circumstances?"

He thought for a moment in silence. Then he shook his head sorrowfully.

"It is what a brave man and a good friend should do," he said; "yet it
seems