They had a stump of a candle, too, for David could see its flickering light. And there was a kind of a lamp out on the floor beyond, and it burned with a sputtering and a hissing and a roaring, and it threw a big bluish kind of a flame straight out, like water out of a hose. David watched the men for nearly a minute without saying anything, but he couldn't guess what they were up to. "What are they doing?" he asked at last. "They're putting in the waste pipe and the trap," said the foreman; "but you don't know what that is, of course. They're putting in the pipe that the water runs through when it runs out of the sink." "Oh, I know," David cried. "It's for the dirty water that the pots and pans have been washed in; the soapy water." "That's just right, Davie." "Well," David said, "why do they have to be lying down to do it? I should think they'd rather do it standing up or sitting down." At that, one of the men poked his head out and smiled at David. "You got that just right, too," he said; "but here's where it has to go, and there's no other way that I know of." "The pipe has to be under the sink, Davie, for the water to run into it," the foreman said. "Now come on, and we'll go upstairs again." So the foreman and David went up the back stairs very slowly and carefully, for there were rough boards on those stairs, too; and they went through a door and through the upstairs hall, and through another door into a small square room. The foreman said that that room would be the bathroom. No plaster was on the walls yet, but the laths were all on. And there wasn't any bathtub yet, nor any basin; only some pipes sticking up out of the floor. And David saw the bodies and the legs of two more men. These men had their heads and shoulders through a great square hole in the floor, and their bodies and their legs were lying on the floor and sticking out straight. David laughed. "Water-pipe men are funny men," he said. One of the men lifted his head out of the hole in the floor and smiled at David, but he didn't say anything. "They're putting in the waste pipe and the trap," the foreman said; "that is, the pipe that the water will run through when it runs out of the bathtub. A tub will be here Davie, after the floor is laid." David nodded. "Would you like to be a plumber, Davie?" the foreman asked, smiling. David shook his head. "I think I'd better go now," he said. "My kitty won't know where I am." So the foreman laughed, and he tucked David under his arm and carried him downstairs and out of the front door, and he set him down on the ground. "Good-bye, Davie," said the foreman. "Good-bye," said David. And he took hold of the handle of his cart, and walked home as fast as he could, dragging his cart, and his shovel and his hoe rattled in the bottom of it. When he got home, there was his cat waiting for him.