"We thought we'd come out and see how you're getting along, Bob," said his aunt, smiling at him, while the two girls came forward as she spoke. "I want you to meet my nieces, Bob. This is Ruth Thomas, and this is Edith Atwood--and this young man, girls, is Robert Williams, about whom I spoke." "What a fib, Aunt Bettie," laughed Ruth. "You know you've been talking about him ever since we got off the train, and besides, you called him 'Bob,' not Robert." "May I call you 'Bob,' too?" she asked, looking up at him. "I like it better than Robert. It doesn't take so long to say." "Of course," replied Bob, blushing. "I guess I wouldn't know who you meant if you called me 'Robert,' for I've been called 'Bob' ever since I can remember." "Is that concrete, Bob?" asked Ruth suddenly, as he stopped the engine and brought the drum to a standstill. "What makes it so gray?" "The cement," said Bob, pleased to see her interested in his work. "Is it sticky?" she asked, as she put her fingers into it and stirred around in the mixture. "Why, it's gritty, just like sand, Aunt Bettie," she said looking up. "Of course," said Bob. "That's because it's made of sand and gravel and cement." "May I see you make some?" she asked. "Yes, in a few minutes," he replied; "just as soon as we empty the drum. You'd better stand back a little so that you won't get splashed when the concrete goes into the wheel-barrow," as Tony came forward. "And this is Tony, Bob's assistant, girls," said their aunt. "This is Ruth, Tony, and this is Edith." "I-a please to meet da young-a ladies," said Tony, more embarrassed even than Bob had been, as he awkwardly placed the wheel-barrow under the drum. As soon as the drum was empty, Bob measured out a charge of four parts gravel, two parts sand and one part cement, and then started the engine and dumped them into the drum, where he added sufficient water for the mixing. "How do you tell how much water to put in?" asked Ruth. "Oh, we learned that by experience," said Bob. You see the mixer has a tank on top that holds the right amount, but this may be varied if you like. The concrete must be wet enough so that it quakes, but not thin enough to run like water." "Let me put in the water next time, Bob, won't you?" she asked. "Say, Aunt Bettie, may I help Bob mix his concrete?" "You better come to the house and help me," replied her aunt laughing. "Bob and Tony, I'm afraid, would only find you in the way." "All right," said Ruth, "but on Monday I'll help you, Bob," and she started for the house with her aunt and cousin, the latter Bob now recalled had not spoken a single word, beyond the introduction. "I'm going to help Bob mix concrete on Monday, Uncle Joe," said Ruth at supper that night. "I know how it's done. You take four parts of cement, two of sand and one part of gravel, and put them in the, 'What do you call it, Bob?'" "Drum," said Bob. "Yes, drum," repeated Ruth. "You see, Uncle Joe, I know how to mix it."