Chapter
19
IMAGINE YOURSELF the size of a microscopic microbe and that you are standing on the outside of a tennis ball, somehow miraculously suspended in space. The surface of the tennis ball would drop away from you in all directions, and no matter where you looked there would be a well defined horizon. Suddenly you are transported to the interior of the tennis ball, which is illuminated by a stationary sun hanging in its exact center. In all directions the interior surface of the hall would curve upward and there would be no horizon. Thus it was with me, as I stood beside that river in Pellucidar. It was as though I stood in the center of a shallow bowl some three hundred miles in diameter. The air was clear, the sun was bright, and under these conditions I assumed that the limit of m
