mitive men had concerning the form and substance of their world.

"The Mahars say it is round, like the inside of a tola shell," he
answered, "but that is ridiculous, since, were it true, we should fall
back were we to travel far in any direction, and all the waters of
Pellucidar would run to one spot and drown us. No, Pellucidar is quite
flat and extends no man knows how far in all directions. At the edges,
so my ancestors have reported and handed down to me, is a great wall
that prevents the earth and waters from escaping over into the burning
sea whereon Pellucidar floats; but I never have been so far from Anoroc
as to have seen this wall with my own eyes. However, it is quite
reasonable to believe that this is true, whereas there is no reason at
all in the foolish belief of the Mahars. According to them
Pellucidarians who live upon the opposite side walk always with their
heads pointed downward!" and Ja laughed uproariously at the very
thought.

It was plain to see that the human folk of this inner world had not
advanced far in learning, and the thought that the ugly Mahars had so
outstripped them was a very pathetic one indeed. I wondered how many
ages it would take to lift these people out of their ignorance even
were it given to Perry and me to attempt it. Possibly we would be
killed for our pains as were those men of the outer world who dared
challenge the dense ignorance and superstitions of the earth's younger
days. But it was worth the effort if the opportunity ever presented
itself.

And then it occurred to me that here was an opportunity--that I might
make a small beginning upon Ja, who was my friend, and thus note the
effect of my teaching upon a Pellucidarian.

"Ja," I said, "what would you say were I to tell you that in so far as
the Mahars' theory of the shape of Pellucidar is concerned it is
correct?"

"I would say," he replied, "that either you are a fool, or took me for
one."

"But, Ja," I insisted, "if their theory is incorrect how do you account
for the fact that I was able to pass through the earth from the outer
crust to Pellucidar. If your theory is correct all is a sea of flame
beneath us, where in no peoples could exist, and yet I come from a
great world that is covered with human beings, and beasts, and birds,
and fishes in mighty oceans."

"You live upon the under side of Pellucidar, and walk always with your
head pointed downward?" he scoffed. "And were I to believe that,