fauna and flora which we have seen convince you that you are not in the world of your birth? And the horizon—could it present the strange aspects which we both noted unless we were indeed standing upon the inside surface of a sphere?"

"But the sun, Perry!" I urged. "How in the world can the sun shine through five hundred miles of solid crust?"

"It is not the sun of the outer world that we see here. It is another sun—an entirely different sun—that casts its eternal noonday effulgence upon the face of the inner world. Look at it now, David—if you can see it from the doorway of this hut—and you will see that it is still in the exact center of the heavens. We have been here for many hours—yet it is still noon.

"And withal it is very simple, David. The earth was once a nebulous mass. It cooled, and as it cooled it shrank. At length a thin crust of solid matter formed upon its outer surface—a sort of shell; but within it was partially molten matter and highly expanded gases. As it continued to cool, what happened? Centrifugal force hurled the particles of the nebulous center toward the crust as rapidly as they approached a solid state. You have seen the same principle practically applied in the modern cream separator. Presently there was only a small super-heated core of gaseous matter remaining within a huge vacant interior left by the contraction of the cooling gases. The equal attraction of the solid crust from all directions maintained this luminous core in the exact center of the hollow globe. What remains of it is the sun you saw today—a relatively tiny thing at the exact center of the earth. Equally to every part of this inner world it diffuses its perpetual noonday light and torrid heat.

"This inner world must have cooled sufficiently to support animal life long ages after life appeared upon the outer crust, but that the same agencies were at work here is evident from the similar forms of both animal and vegetable creation which we have already seen. Take the great beast which attacked us, for example. Unquestionably a counterpart of the Megatherium of the post-Pliocene period of the outer crust, whose fossilized skeleton has been found in South America."

"But the grotesque inhabitants of this forest?" I urged. "Surely they have no counterpart in the earth's history."

"Who can tell?" he rejoined. "They may constitute the link between ape and man, all traces of which have been swallowed by the countless convulsions which have racked the outer crust, or they may be merely the result of evolution along slightly different lines—either is quite possible."

Further speculation was interrupted by the appearance of several of our captors before the entrance of the hut. Two of them entered and dragged us forth. The perilous pathways and the surrounding trees were filled with the black ape-men, their females, and their young. There was not an ornament, a weapon, or a garment among the lot.

"Quite low in the scale of creation," commented Perry.

"Quite high enough to play the deuce with us, though," I replied. "Now what do you suppose they intend doing with us?"

We were not long in learning. As on the occasion of our trip to the village we were seized by a couple of the powerful creatures and whirled away through the tree tops, while about us and in our wake raced a chattering, jabbering, grinning horde of sleek, black ape-things.

Twice my bearers missed their footing, and my heart ceased beating as we plunged toward instant death among the tangled deadwood beneath. But on both occasions those lithe, powerful tails reached out and found sustaining branches, nor did either of the creatures loosen their grasp upon me. In fact, it seemed that the incidents were of no greater moment to them than would be the stubbing of one's toe at a street crossing in the outer world—they but laughed uproariously and sped on with me.

For some time they continued through the forest—how long I could not guess for I was learning, what was later borne very forcefully to my mind, that time ceases to be a factor the moment means for measuring it cease to exist. Our watches were gone, and we were living beneath a stationary sun. Already I was puzzled to compute the period of time which had elapsed since we broke through the crust of the inner world. It might be hours, or it might be days—who in the world could tell where it was always noon! By the sun, no time had elapsed—but my judgment told me that we must have been several hours in this strange world.

Presently the forest terminated, and we came out upon a level plain. A short distance before us rose a few low, rocky hills. Toward these our captors urged us, and after a short time led us through a narrow pass into a tiny, circular valley. Here they got down to work, and we were soon convinced that if we were not to die to make a Roman holiday, we were to die for some other purpose. The attitude of our captors altered immediately as they entered the natural arena within the rocky hills. Their laughter ceased. Grim ferocity marked their bestial faces—bared fangs menaced us.

We were placed in the center of the amphitheater—the thousand creatures forming a great ring about us. Then a wolf-dog was brought—HYAENODON Perry called it—and turned loose with us inside the circle. The thing's body was as large as that of a full-grown mastiff, its legs were short and powerful, and its jaws broad and strong. Dark, shaggy hair covered its back and sides, while its breast and belly were quite white. As it slunk toward us it presented a most formidable aspect with its upcurled lips baring its mighty fangs.

Perry was on his knees, praying. I stooped and picked up a small stone. At my movement the beast veered off a bit and commenced circling us. Evidently it had been a target for stones before. The ape-things were dancing up and down urging the brute on with savage cries, until at last, seeing that I did not throw, he charged us.

At Andover, and later at Yale, I had pitched on winning ball teams. My speed and control must both have been above the ordinary, for I made such a record during my senior year at college that overtures were made to me in behalf of one of the great major-league teams; but in the tightest pitch that ever had confronted me in the past I had never been in such need for control as now.

As I wound up for the delivery, I held my nerves and muscles under absolute command, though the grinning jaws were hurtling toward me at terrific speed. And then I let go, with every ounce of my weight and muscle and science in back of that throw. The stone caught the hyaenodon full upon the end of the nose, and sent him bowling over upon his back.

At the same instant a chorus of shrieks and howls arose from the circle of spectators, so that for a moment I thought that the upsetting of their champion was the cause; but in this I soon saw that I was mistaken. As I looked, the ape-things broke in all directions toward the surrounding hills, and then I distinguished the real cause of their perturbation. Behind them, streaming through the pass which leads into the valley, came a swarm of hairy men—gorilla-like creatures armed with spears and hatchets, and bearing long, oval shields. Like demons they set upon the ape-things, and before them the hyaenodon, which had now regained its senses and its feet, fled howling with fright. Past us swept the pursued and the pursuers, nor did the hairy ones accord us more than a passing glance until the arena had been emptied of its former occupants. Then they returned to us, and one who seemed to have authority among them directed that we be brought with them.

When we had passed out of the amphitheater onto the great plain we saw a caravan of men and women—human beings like ourselves—and for the first time hope and relief filled my heart, until I could have cried out in the exuberance of my happiness. It is true that they were a half-naked, wild-appearing aggregation; but they at least were fashioned along the same lines as