“How’s the work going on over there?” Tom asked. “The dam? Oh, there’s going to be quite a lake over there. Only there’s a lot of trees down on the lower reaches of the mountain that have got to be filled.” He lingered in the doorway as if quite willing to explain. “You see, if they rot, why then there’s nothing left to hold the earth together on those slopes. What’s the result? It slides down into the lake and fills it up with mud. In the end they have to dredge it. That’s what they call erosion--earth falling away from where it belongs because there are no roots to hold it together. You see trees are important.” “Well, I guess,” said Tom. “The federal government is doing a lot of that out west,” said the visitor. He seemed quite willing to explain this interesting work, pausing still in the doorway, and smiling as if to encourage further questions. “Well, I’m mighty glad you dropped in on us,” said Tom. “My name is Slade and my chum’s name is Gaylong.” “Glad to know both of you,” said the visitor, with a little nod of acknowledgment. “My name’s Lawton.” “Don’t you go to camping anywhere else now,” Tom said. “Thanks,” said Lawton briskly; “you’ll see me.” And he hurried away. CHAPTER XXVIII—Three’s Company “Well, there’s my mysterious fugitive smashed in the head,” laughed Tom. “Also my mysterious sounds at the top of the well,” said Brent. “And that’s that,” Tom added. “Mighty nice chap, huh? Boy, that must be interesting work!” “I’m disappointed,” said Brent; “these prosaic calls are getting monotonous. We heard footsteps in the night and they turned out to be a Boy Scout----” “Oh, there’s nothing prosy about Spiff,” laughed Tom. “And now comes this tree dentist or whatever you call him, with his cement and his explosions----” “Erosion,” said Tom. “It’s mighty interesting work. There’s a lot of that kind of work going on that we don’t know anything about.” “Not a single escaped convict so far!” said Brent. “The only bait-box I’ve seen is full of salt. Conservation experts aren’t getting us anywhere. Escaping Scouts are not snappy enough. I was led to expect an old tottering hunter of the _Covered Wagon_ type, and all I get is a dentist. I suppose the next person to come stealing in on us will be a life insurance agent. How about going fishing this afternoon?” “Let me tell you one thing,” said Tom; “these fellows are a mighty interesting lot, these government fellows; surveyors and rangers, irrigation fellows and all that--and----” “Dentists,” said Brent. “Well, I hope you’ll give him the glad hand,” said Tom. “He can fill all the cavities and do all the crown and bridge work and painless extractions he wants around here,” said Brent, “as long as he doesn’t bother me.” “He doesn’t do it himself,” said Tom. “Well, he can blaze all the trails he wants,” said Brent. “I should think his glasses would fall off climbing trees. He makes a noise like a professor, doesn’t he? What is it--_corrosion_?”