They had already traveled a distance at least equal to two city blocks. The tunnel had made various turns, but as yet they had not encountered any side excavations. This was fortunate, as it permitted them to continue ahead without any doubt as to the proper passage.
Presently, to the unspeakable delight of all three, the air became less foul.
"We are almost there," cried Nattie, cheerily. "Courage, courage!"
It was time. The torches, mere pine slivers, had burned away until only a few inches remained. They had started with an ample supply, but while passing the ghastly array of skeletons, Sumo had dropped the reserve bundle in his terror.
Suddenly the one carried by Mori gave out; then Nattie's gave a feeble splutter and expired. Presently, however, the floor in the tunnel began to brighten, and finally, on turning a corner, a feeble speck of light became perceptible in the distance.
"The end, thank God!" shouted Mori.
The echoes of his voice had hardly died away when a most dreadful thing happened. Without the slightest warning to herald its approach there came a terrific rending shock. It seemed as if the very bowels of the earth had collapsed in one great crash.
Nattie and Mori and Sumo were thrown to the ground with violent force, and there they lay mercifully deprived of consciousness, while around them the walls and roof and floor of the tunnel heaved and pitched in the throes of an earthquake.
The disturbance only lasted a moment, but it was some time before the little party recovered. Nattie was the first to stagger to his feet. The torch had gone out, leaving an impenetrable darkness. The welcoming light—the light proclaiming the exit from the tunnel—had disappeared.