Elated with the idea, Og proceeded to find another stone that he could handle, and after a search he picked up one about the size of his fist that was black and extremely hard. Og did not know that he had fortunately found a piece of flint. With this and the rude hammer head in his hands he sought out a flat rock, and sitting down with the hammer head between his knees, proceeded with his task of shaping it, while the guards of the tree people looked on from the mouth of the canyon with apish inquisitiveness.

But Og had not chipped more than a half dozen strokes when he made a startling discovery, one that made him experience a strange mixture of fear and elation. He proceeded first to chip away a jagged corner of the hammer head with his piece of flint, when suddenly, and much to his astonishment, the flint gave off a series of fire sparks. So startled was Og that he dropped the black stone and sat staring at it in amazement. He had discovered fire again.

After a time he picked up the flint and felt it carefully. It was not hot, yet it contained fire. That was strange. It was black. The cooling volcanic rock from which he had lighted his resinous torch first was also black. Was this, then, the same kind of fire rock? Og searched about and found a stick. He touched it to the flint; held it there a long time yet no tiny spirals of smoke rewarded him as he expected. Still he knew the fire was in the rock. It leapt out when he struck it against another rock. He tried it, and with the second tap more sparks flew.

Og examined the flint carefully; turned it over and over, felt it again, tried once more to light the stick, then, still holding it in his hand, he sat and thought and thought and thought, until his brain grew tired. The fire was in the rock, of that he was certain, but how to get it out and in his possession, under his control, was a vexing question.

Ere long the hammer head was shaped to his satisfaction. To secure a handle and tough bark with which to lash both stone and stick together was not difficult, for among the rocks was scrubby vegetation that yielded him both of these necessities. Og put his now valuable chipping flint in a safe place, while he worked diligently but carefully at making the rest of his hammer.

The coming of night was fraught with unpleasantness for Og. A prisoner there in the canyon, with the menacing entrance of that mysterious black cave behind him, and the guards of the tree people on the alert and closing his only way of escape, made more acute his inherent fear of the hours of darkness. How glad he was to have the company of the faithful wolf cubs then.

Before night was well upon him, Og and the wolf cubs climbed as high as they could on the sides of the canyon and, huddled behind a huge bowlder, with their faces turned toward the rear of the canyon and the entrance of the cave.

And it was well for Og that he decided to climb part way up the canyon wall and take shelter behind the bowlder, for hardly had he become comfortably huddled down with the wolf cubs nestled close to him, when the narrow confines of the canyon echoed with a wild blood-chilling roar and, through the blackness of the canyon, Og could see in the entrance of the cave two glowing eyes and the outline of a huge sabre-toothed tiger.

Softly, yet swiftly, Og reached out and covered the mouths of the wolf cubs, for he knew that a whimper or growl from them would bring the great beast down upon them in an instant. Then like statues, without the movement of a muscle, they sat there and watched the great beast come slowly forth from the cave, stretch itself and yawn, then test the wind by throwing up its massive, ugly head. And as Og watched just a glimmer of the real idea for his imprisonment in the canyon took shape in his brain. Had they left him there as a sacrifice to this beast?