Being open-hearted, he told his folks about his purchase, and they were inclined to find fault with him, though I do not know why. He seemed never to tire of his book and ball, but would change from one to the other, and for some days was as happy as a king is supposed to be. Then came his bad luck. He was tossing his ball upon the roof of the house, and catching it as it came down; but by and by it did not come down--it bounded into the tin eave-trough and rolled slowly along till it came to the big pipe that led to the cistern, and into this it dropped, and went whirring down, and stopped somewhere with a faint plash. For once in his life, Johnny felt as if the world had slipped from under him. For a few minutes he was bewildered; then came the joyful assurance that his Steele would help him out of his trouble, and if Steele couldn't, there was the schoolmaster. The first thing he did was to lift the cover off the cistern, though he knew well enough the ball was in the pipe, as he well remembered that it ran nearly to the bottom of the cistern and then made a sharp bend upward, "so that the water mightn't wear the cement," the mason told him. He found the water quite low, but not low enough to show the mouth of the pipe. Of course, there was no ball in sight. He closed the cistern with a groan, and got out his new book on natural philosophy. First he glanced at optics; but that did not help him to see his way; then at hydrostatics and hydraulics. It was of no use; nothing seemed to hit the case. Then he gave it up, put his book away, and went to consult the school-master. Johnny found him among his books, and told him all about it. "Have you tried to fish it out with a hook and line?" Johnny's face brightened. "No, sir, I never thought of that." "All right; you couldn't do it. Besides, if you could, it wouldn't be scientific," said the school-master. "Now, go home, take a ten-foot pole, and measure the distance from the eaves to the water in the cistern, then find the diameter of the pipe, and on my way to school to-morrow morning I will tell you the three things necessary for recovering your ball." Johnny fairly flew home, got a pole, measured the distance from eaves to water and found it to be twelve feet; measured the pipe and found it to be two inches and one-half. Then he put away the pole, did his chores, ate a hearty supper, and went to bed. He was up bright and early next morning, and got quickly through his chores, so that when the school-master stopped, on his way to school, he was ready to see about the ball. "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."