From behind the dead camel Guy and Melton poured in a hot fire that checked their impetuous advance instantly, and before they could rally for another charge, both had bolted into the gloomy hole, and the stone was deftly rolled into place. CHAPTER XXI. CUT OFF FROM THE OUTER WORLD. The lamp was lit instantly, and without a moment's delay Guy led the party at full speed down the corridor until the descent was reached. "Now hurry down, all of you," he cried. "You have a flask of powder about you, Canaris. Give it to me." "What are you going to do, Chutney?" asked Melton in alarm. "Put an end to all pursuit," was the stern reply; and, seizing the flask, he placed it on the ground, and pouring a little powder on a strip of linen torn from the lining of his blouse, he deftly rolled a fuse and inserted one end in the mouth of the flask. His intentions were apparent. The roof and walls of the passage were of loose earth and stone. A blast would bring them down in an avalanche. Canaris attempted to expostulate, but Guy drove them all down the slope and applied a match to the fuse. It was high time, for up the passage shone the gleam of torches. The enemy had effected an entrance. Guy joined his companions on the shore of the river, and almost instantly a terrific explosion took place. It seemed to rend the earth. A tremendous crash and rumbling noise followed, and then all was quiet. The concussion put out the lamp, but as soon as it was lighted again Guy ran up to see the result of his attempt. No trace of the passageway existed. In its place was a grim wall of earth. The full significance of what he had done now flashed into Guy's mind and he gazed blankly into the faces of his comrades. "We are buried alive," said Melton bitterly. "We are as dead to the world as though we were in our coffins." "We have simply burned our ships behind us, that is all," replied Chutney. "Now for the river and freedom." They went back and sat down beside the swiftly-flowing water. "Bless me if I know whether I am on my head or my feet," said Sir Arthur. "What on earth does this mean?" "It means that these brave fellows have saved us from a fate worse than death," cried the colonel; "that is all I care to know at present." "I will explain all," said Guy. He straightway related everything that had happened from the time they were separated on the way to Harar to the discovery of the underground river and the daring plan for the rescue of the prisoners. The colonel could scarcely repress his astonishment as he listened to the wonderful story, and at its conclusion he embraced his rescuer warmly. "We owe you our lives," he said fervently. "Never was a braver deed attempted, never was a rescue more marvelously carried out. Ah, I can never repay the debt. A grateful country will reward you, Captain Chutney. England shall know of your heroism."