‪“I see no reason why not. We will make a valiant effort. It is better than tamely submitting to death.” ‪“Indeed, much better.” ‪“Here goes!” Frank advanced and placed both hands upon one of the iron bars of the gate. It was thickly encrusted with rust; yet neither looked for the result which followed. Frank gave the gate a quick, sharp pull. Then he gave a leap backward. It was just in time. He was not a moment too soon. Down came the whole affair in a clanging heap. If it had struck Frank he might have been seriously injured. But fortunately it did not. The action of time had rusted hinges and locks, and the gate was just ready to fall. A great cloud of dust was raised which nearly overwhelmed the two explorers. They emerged from it completely covered and wheezing and puffing. ‪“Jupiter!” gasped Tony, “there’s no question about getting out of here now, Frank.” “No, not if this dust don’t kill us,” replied Frank. ‪“Whew! it is fearful.” After a time, however, the dust cloud was dispelled and they emerged all safe. Then the first impulse was to break through the archway. This they did and came to a flight of stairs. Up these they ran at full speed. Arrived at the top, they were confronted by an astounding fact. They stood in a small square chamber. So far as they could see there was no door or window or other mode of exit. Only bare walls of stone were about them upon all sides. ‪“Well!” exclaimed Frank, in amazement. ‪“What the deuce does this mean?” ‪“Where are we?” ‪“Sure enough.” ‪“Can you see any way out of here?” ‪“I cannot.” The two men looked at each other blankly. It was some time before either ventured to speak. ‪“This is the toughest yet,” said Buckden, finally. ‪“What is your idea, Frank?” A light broke across the young inventor’s handsome face. ‪“I have an idea!” he cried. ‪“What is it?” Frank went and critically examined the walls of the chamber before he ventured to answer. ‪“This is a sealed chamber,” he said, finally. ‪“It is sealed that nobody may find the secrets of this underground charnel house.” ‪“A sealed chamber!” gasped Buckden. ‪“My God! then we are lost, for that is equivalent to being buried alive. Our end has come!” CHAPTER XI. OUT OF IMPRISONMENT. It was a terrible despairing cry which Tony Buckden gave. It came from the depths of his soul, and embodied utter hopelessness. Indeed, the situation looked to be a desperate one. If it was indeed true that they were the inmates of a sealed chamber their fate seemed sealed. What was to be done? Surely they could not submit to a slow lingering death by starvation in that wretched place. Frank went forward and began to examine the masonry of the chamber walls. The stone was a peculiar sandstone, and while it showed evidence of age and the discolorations of time it was yet firm and hard. But the mortar would yield to the point of the knife. Frank at once began work upon it.