"Yes, David, we have every book and pamphlet catalogued. And I am adding something new," continued the professor. "I am getting the autographs of many of the writers and pasting them on the fly-leaves. And where a writer dies and I get a printed obituary notice I paste that in the back of the book. I think it adds something to a volume to know about the writer and to have his or her autograph." "Fine, Professor!" cried Dave, and tapped him on the shoulder. "My, but it is nice here! Much better than the old farm, eh, and the poor-house that I came from!" The old gentleman nodded several times, and the tears stood in his eyes. "Yes! yes! It is very, very nice. I have found real friends, and I am thankful, very thankful!" And he continued on his way down the hall, wiping his eyes with his handkerchief. On the stairs Dave met Jessie. She was in a fresh dress of white, and had a rose in her hair. "How pretty you look!" he whispered, as he took her arm. "Just like a--a picture!" And then Jessie blushed and that made her look prettier than ever, if such a thing were possible. Dave's father and Mr. Wadsworth had come in, and both were glad to see the boy back. Soon dinner was announced, and all sat down to the long table, Dave between his sister and Jessie. It was old Professor Potts who asked grace; and then some rapid-fire conversation followed, the girls and the others demanding to know all about what had happened at Senator Morr's home, and about the lost mine. "It certainly sounds like a romance!" declared Dave's father, referring to the lost mine. "But I have heard of such things before," answered his brother. "I know of several valuable mines in South America that were lost through earthquakes. Landslides have not only buried mines, they have buried cities as well." "Oh, Dave, supposing you went to look for that mine and there was another landslide!" gasped Jessie, and turned pale. "That's a risk we'd have to run," was his answer. "But I'd be very careful as to where I went, Jessie." "I don't know about this," put in Mr. David Porter, with a grave shake of his head. "Better take the trip through Yellowstone Park, Dave, and let the Landslide Mine slide," and he smiled, faintly. "Oh, I promised Roger that I'd go with him,--and Phil is going, too!" pleaded Dave. "We'll be very careful." "I might go with you myself, only I think I ought to stay with the party to go through the Park," said Dunston Porter. "Yes, we want you with us!" cried Laura. "I don't like this at all!" pouted Jessie, and looked somewhat reproachfully at Dave. "Oh, you mustn't take it that way!" cried the youth. "Why, we'll be with you on the trip to the Park, and then we'll join you on the tour a little later. You are to stay at least four weeks, remember. Well, if we spent two or even three weeks looking for that mine we'd still have a week in the Park--and one can go through in six days, so the circular says."