"Good morning, Johnny! Glad to see you on hand. How long's the pipe?"
"Twelve feet, sir."
"Diameter?"
"Two inches and a half, sir."
"Ah! 2-1/2 square multiplied by .0034, and that product by twelve feet, which is—"
"144 inches," Johnny quickly suggested.
"Will give the contents of the pipe in gallons," added the schoolmaster. "You're quick at figures, tell me the answer."
Johnny groped among the odds and ends of his jacket pocket for a minute, and then fished out a stubby lead-pencil, much chewed at one end, and picking up a piece of smooth board, ciphered away swiftly and carefully a few moments.
"3.06 is what I make it, sir."
"Very well; we'll call that right; that would be a little over a pailful—say a pailful and a half. Now get a ladder to go up to the roof with."