punishment for his temerity in attempting to invade the sanctity of their ancient solitude.
For two days Tarzan sought futilely for some clew to the whereabouts of the machine or its occupants. He cached portions of his kills at different points, building cairns of rock to mark their locations. He crossed the first deep gorge and circled far beyond it. Occasionally he stopped and called aloud, listening for some response but only silence rewarded him—a sinister silence that his cries only accentuated.
Late in the evening of the second day he came to the well-remembered gorge in which lay the clean-picked bones of the ancient adventurer, and here, for the first time, Ska, the vulture, picked up his trail. "Not this time, Ska," cried the ape-man in a taunting voice, "for now indeed is Tarzan Tarzan. Before, you stalked the grim skeleton of a Tarmangani and even then you lost. Waste not your time upon Tarzan of the Apes in the full of his strength. But still Ska, the vulture, circled and soared above him, and the ape-man notwithstanding his boasts, felt a shudder of apprehension. Through his brain ran a persistent and doleful chant to which he involuntarily set two words, repeated over and over again in horrible monotony: "Ska knows! Ska knows!" until, shaking himself in anger, he picked up a rock and hurled it at the grim scavenger.
Lowering himself over the precipitous side of the gorge Tarzan half clambered and half slid to the sandy floor beneath. He had come upon the rift
