kites of various kinds—Wind gauges and wind force—Patents and how to secure them—A simple sundial—How to make an oval flower bed.

185 IX. Tides
The "why" of the tides explained—Globular form of the earth proved—Day and night—Phases of the moon—Attraction of the sun and moon—Newton's theory of the tides—Height of tides—A simple hygrometer—The Australian boomerang—Theory of the pump. 212 X. Wall Making and Plumbing
Protecting the river bank—Concrete retaining walls—Big dams in the West—Galveston sea wall—The great dam across the Nile—Proposed irrigation works in Babylon—Some properties of light and sound—Hints on amateur plumbing—The peppermint test—Barometers of various kinds—Thermometers, and their uses—Something about steel springs—How to make a cross-bow—The gyroscope and its uses. 237

PART II

I. Some Practical Advice
The inventor, ancient and modern—Barriers to mechanical progress in the past—Laws of gravitation—How to adjust sewing machines. 271 II. Mechanical Movements
Coffee mills—Pulleys—Pumps—Pistons—Levers—Steam engine and water wheel governors, etc. 306 III. The Weather and Indoor Work
How to make a rain gauge—Hail—Snow—Designing, making and inflating paper balloons—Magnetized watches—A boy's wheelbarrow—Vacuum cleaners. 349 IV. Motors and Typewriters
Motors, gasolene and steam—Automobile frames—The modern typewriter—Directions for securing copyrights. 387

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ILLUSTRATIONS

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PART I

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I

A PATHWAY OF CEMENT

I do wish papa would buy the land from Mr. Breigel. The weather will soon be fine enough to play out of doors!"

So said Jessie Gregg, a rosy-cheeked girl of twelve, to her eldest brother, Fred, one evening in March, as they stood in the porchway of their home, situated near the bank of the Passaic River, a few miles from the city in which Mr. Gregg had his business offices.

"Why, Jessie," said Fred, "papa told me this morning, at breakfast, he expected to close the deal, that is, get the deed of the property, this afternoon. I am just as anxious as you are to have the matter settled, for if he gets the land, I will have a lot of work to do, and I want to commence it right away. The land must be ours, for papa is later than usual this evening. Oh! there's the train just coming in; he will be here in a few minutes, and then we'll know."

"Oh, Fred! he and George are coming now. I see them at the turn of the road. I'll run to meet them." Away she scampered, and almost upset her father by jumping into his arms, as she was quite a plump, husky girl and evidently a pet, for her father kissed her fervently as she slid from his arms to the ground. Then the three trudged homeward.

"Jessie," said George, a younger brother, "I have a secret for you if you won't tell Fred, until papa has told him."

"What is it?"

"Papa has bought the land, and has got it in his pocket."

"Oh! I am so glad," said Jessie, "but how can he have it in his pocket."

"George means that I have there the papers, deeds, conveyances, and receipts, giving me the sole ownership of the land, and all that is on it, including the trees, old barn, and other structures; so, girlie, you can get down to the river now without having to climb a fence."

Fred met his father on his arrival at the house, but was too well behaved to ask him about the land, though he was as anxious to know as he could be. His father saw the boy's anxiety and after tea asked him to go with him into his den, a little room nicely fixed up some time previous, containing many articles of wood, brass, and plaster of Paris, Fred and George had made during the past winter. Jessie, also, had contributed many little things toward the decoration of "the lion's den," as she called