After a little he began to move along, taking care, however, to keep close to the wall, for he did not know how wide the ledge, as he judged it, might be. For perhaps a hundred yards he progressed thus. Always before he took a step he reached out with one foot before him, fearing to encounter vacancy.
Suddenly he found he was on the edge of a void, and shrank back, clinging to the wall with the desperation of fear. It was some seconds before he dared to move again. He could feel the sweat rolling off him, the cold, pricking sweat of fright.
By a supreme effort he mastered himself. He found a loose bit of rock at his feet. Cautiously he cast it into the darkness in front of him. There was a long silence, and then, as if from miles away, came a tiny tinkle.
Jack shuddered.
He had narrowly escaped pitching head first into a bottomless abyss. He carefully retraced his way down the ledge. Suddenly his feeling fingers discovered another crack. This one ran vertically upward like a chimney, almost, at least so far as he could determine by the sense of touch.
A wild hope surged over him. This crack perhaps ran up to the surface of the earth! Recalling an old school-boy trick, he “spreadeagled” himself into the crack. He reached out his hands to either side of the “chimney” and lifted himself a little.
Then he wedged his toes in either side. Thus he painstakingly mounted, praying within himself that the walls of this natural shaft might not widen and make further progress impossible.
It was terribly slow work, though. Time and again he was on the point of giving up, but always the tough spirit of his indomitable old sea-faring ancestors kept him at his task.
Foot by foot he toiled upward, till he estimated he had climbed some thirty feet. And then suddenly: Light! The blessed light of day! High above it was, but unmistakably the light of the outside world was streaming into this hideous subterranean chamber. It gleamed down into the shaft he was painfully ascending, shining like a blessed beacon of hope. It appeared to filter through some sort of net-work of greenery.
Wild with hope, he climbed on till at last he burst his way through a canopy of creepers and vines that obscured the mouth of the natural shaft. He clambered out beneath the blessed sky. As he fell exhausted, prone on the rocks, he heard a cry.