This seemed to be entirely the correct scheme and Dick and Doctor Dan lost no time in carrying it out. The only objection Dick made was that they would have to work in the dark, but this Doctor Dan soon disposed of by producing a lantern, which he had brought along with him and hidden among the rocks in the canyon. Then they hurried on to the stone steps and were soon down in the cavern once more. Armed with the lantern, Doctor Dan went ahead and had no difficulty in following his own trail, for the floor of the cavern was composed of soft sand and the guide’s footsteps plainly showed. Now we have said but little about Dick’s anxiety for Charley, because there has been so much to tell, but it was of the keenest kind. As they walked along by the side of the underground river Dick kept shouting Charley’s name, as he had done before, hoping to get an answer, and before they had gone any great distance sure enough he did. Of course this threw the whole party into a great state of excitement and they hurried forward and soon came upon Charley, who was running toward them along the river bank. “It’s all right, Dick!” he shouted. “I came down as easy as you please. No trouble about the Boiling Pot once you know how to handle yourself in it. Hello, doctor. How in the world did you get over this side of the lake? Oh, Dick, I’ve got such news to tell!” Charley was so excited that he could hardly wait until Dick had told what happened at the hut, although he insisted upon hearing it all before he would explain. “We have got to look sharp or that scoundrel Mudd will finish us up sooner or later,” he exclaimed. “Now, then, Dick, what do you suppose I have found?” “Give it up, but I wish you would tell,” replied Dick. “Out with it! We are all dying to hear.” “Old P. D. asleep!” “What!” “Old P. D. asleep, I tell you. Oh, I mean it! This cave is a wonderful place. You haven’t seen half of it yet, nor I, either, for that matter. You see I landed on the other side of the river this time and I had to swim across, but before I did it I browsed around there a bit and made my discovery. I was working down to the steps when I met you. Keep the lantern down lower, doctor, so that I may follow my trail. There, that’s right. Dick, I believe we can catch old P. D. after all and hold him till we can get Prof. Poynter up here.” “It would be a big triumph if we could,” said Dick. “But I am waiting to have you tell me more about it, Charley. How did you make all these discoveries in the dark?” “Why, it wasn’t done in the dark,” replied Charley. “I found a lantern here. It went out a few moments ago for want of oil, so I left it behind me. Oh, I haven’t told you all I have discovered yet.” “Let’s have the rest of it then,” said Doctor Dan. “Hello! Here’s your lantern now.”