The Scientific American Boy Part 18

THE ELASTIC BELLY BAND.

An important change was made in the belly band of the kite. The lower strand was made elastic by tying it fast to a number of heavy rubber bands, as in Fig. 242. When flying the kite, if a sudden, strong puff of wind struck it, the elastic belly band would give, tilting up the lower end of the kite so that the wind pa.s.sed under; but as soon as the gust had pa.s.sed the rubber bands would draw the lower end of the kite back against the wind. The elastic belly band had the effect of making the kite rise almost vertically. Sometimes it would even sail square overhead. The 8-foot kite was a very powerful one. To hold it we had to use a very strong cord, the kind used by upholsterers for tying down the springs in a chair or a sofa.

PUTTING THE KITES TO WORK.

Bill tested the strength of the kite once by hooking a spring scale to the kite string. The scale was made to register weights up to 25 pounds.

But our kite yanked the pointer immediately past the 25-pound mark as far as it would go. We judged from this that the kite would lift at least 40 pounds. Such a pull as this it seemed a pity to waste, but how to utilize the power was a problem until one day, when the kite was soaring up on a south wind, Dutchy suggested that we tie it to one of the canoes and go sailing up-stream. We tried the trick at once, but it didn't work very well, because the canoe was too light. The kite would drop unless there was a heavy pull on the string. We had better success with the scow, however, which provided a sufficient drag on the kite, and with the two kites to pull us we sailed a long ways up-stream, drifting down with the current when we had gone as far as we cared to.

THE DIAMOND BOX KITE.

[Ill.u.s.tration: Fig. 243. The Scow Towed by Kites.]

[Ill.u.s.tration: Fig. 244. Cleat for Spreader.]

[Ill.u.s.tration: Fig. 245. Corner Stick and Spreader.]

[Ill.u.s.tration: Fig. 246. The Narrow Frame.]

[Ill.u.s.tration: Fig. 247. Tacking on the Cloth.]

[Ill.u.s.tration: Fig. 248. Forked End of Long Spreader.]

Professor Keeler also gave us instructions for making a diamond-shaped box kite, and though we never built one, it may not be amiss to publish his instructions here. I quote from the chronicles of the S. S. I. E. E.

of W. C. I.:

"Materials: Four sticks, 1/4 inch thick by 5/8 inch wide by 44 inches long, for the corner sticks. Two sticks, 1/4 inch thick by 5/8 inch wide by 15 inches long, for the short spreaders. Two sticks, 1/2 inch square by about 38 inches long, for the long spreaders. Two strips of cloth 81 inches long, hemmed at each edge to a width of 13 inches. Whittle out twelve cleats to the form shown in Fig. 244. At the ends of the 15-inch spreaders nail cleats on each side with long wire brads, so as to form forks, as shown in Fig. 245, in which two of the corner sticks are held.

The short spreaders are fastened to the corner sticks, 7 inches from the ends, with brads driven through the cleats, making the frame (as in Fig.

246). To prevent the frame from skewing off sidewise it should be braced with wire running diagonally across from one corner stick to the other.

Ordinary soft stovepipe wire will do. Care must be taken to have the spreaders meet the corner sticks squarely or at right angles. Now take one of the cloth strips and sew its ends together to form a band. The end should be lapped about an inch and fastened with the sailor st.i.tch (see Fig. 223). The same should be done to the other cross strip, and then each band should be marked off with pencil lines at four points, all equidistant from each other. The two bands may now be tacked to the two ends of the frame with opposite pencil lines over the edges of the corner sticks, as in Fig. 247. The two remaining corner sticks are then nailed to the bands at the two other pencil lines. These corner sticks will now be braced apart by the long spreaders, which are notched to the right length to stretch the cloth taut. A cleat is nailed over each notch, as shown in Fig. 248, forming forks to hold the corner pieces.

The long spreaders are now forced down until they meet the short spreaders, to which they are tied with waxed string. The long spreaders may be nailed to the corner sticks by driving brads right through the cloth into the cleats and the sticks. The belly band may be fastened to any one of the corner sticks at the spreaders, and from the points where it is tied it should measure about 45 inches in length. The point where the main string should be attached to the belly band may be best determined by experiment."

[Ill.u.s.tration: Fig. 249. The Diamond Box Kite.]

CHAPTER XXI.

THE WATER WHEEL.

Summer found us again on Willow Clump Island with heads full of new ideas. Bill had come across an old copy of Ewbanks' "Hydraulics" in the school library. It was a book describing machines of the ancients--princ.i.p.ally devices for raising water. Rather dry reading, I thought, even though it was a wet subject; but Bill seemed to find it absorbingly interesting. I came in late one afternoon, after a glorious game of baseball, only to find Bill poring over the yellowed leaves of the "Hydraulics" as fascinated as most fellows would be over a detective story. It exasperated me to note that he thought more of this old book than he did of our baseball team.

"Bill," I exclaimed, "what's got into you? I can't for the life of me see what is so entertaining in that prehistoric book."

"Oh, go way. Don't bother me," was the surly reply.

But I wouldn't be put off that way. Quickly I s.n.a.t.c.hed the book from his grasp and threw it out the window.

"Now, sir," I cried, "maybe you will kindly explain to me why you persist in studying that old volume, to the neglect of our baseball team."

"Don't get so excited, old chap," he replied. "That book is all right.

I'm studying up some new schemes for next year's expedition to Willow Clump Island. Why, there are lots of things in that old book that we can make." And he proceeded to unfold his plans, sketching out some curious designs of water wheels and pumps.

By the time school closed for the summer Bill had thoroughly digested that volume, and was ready to reconstruct many of the ancient machines.

THE WATER WHEEL.

Our first work on reaching the island was to erect a water wheel, or "noria," as it was called in the book, in front of the camp. It had been a great nuisance to keep our filter barrel full. Every few days we would have to form a bucket brigade, pa.s.sing pails of water up the line until the barrel was filled. Now Bill proposed to do away with all this bother and let the river do the work for us.

SURVEYING FOR THE WATER WHEEL.

We first determined the height of the upper filter barrel above the level of the river. This was done with our surveying instrument, which was set level with the top of the barrel. We sighted with the instrument to a long pole that was held upright at the edge of the water. The pole had been marked off into feet with white chalk marks, and on sighting through the sight holes we found that the hairs came in line with the eleventh chalk mark. The top of the filter was, therefore, 11 feet above the level of the river. Bill figured that it would be necessary to construct a wheel about 15 feet in diameter in order to raise the water to the proper height.

[Ill.u.s.tration: Fig. 250. Surveying for the Water Wheel.]

TOWERS FOR THE WATER WHEEL.

[Ill.u.s.tration: Fig. 251. Frame for Large Tower.]

First we built the towers to support the wheel. One tower was 16 feet high and the other only 10 feet. The large tower was made something like a very tall and narrow saw-horse. Two stout poles 17 feet long were flattened at their upper ends and nailed together, with the ends projecting about a foot, as shown in Fig. 251. At the bottom these poles were s.p.a.ced 8 feet apart by a cross bar, and about 9-1/2 feet from the bottom a pair of boards were nailed to opposite sides of the pole to serve as supports for the axle of the water wheel. Another pair of 17-foot poles was now similarly fastened together and then the two pairs were s.p.a.ced about 12 feet apart and connected at the top and bottom with boards.

[Ill.u.s.tration: Fig. 252. The Large Tower.]

[Ill.u.s.tration: Fig. 253. V-shaped Trough.]

At the top two smooth boards were used and these were nailed to the inner sides of the projecting ends, which were tapered off. In this manner a V-shaped trough was formed. The boards were firmly nailed together at their meeting edges so as to prevent them from warping apart. A diagonal brace at each corner made the wedge-shaped tower very substantial. A number of cleats nailed to one of the poles provided a ladder by which we could mount to the top of the tower. The shorter tower was a three-legged affair, made of three 12-foot poles. At first two of these were flattened and nailed together at their upper ends, and they were braced at the top and bottom. The third leg was then nailed in place and braced by cross bars connecting it with the other two poles.

THE WHEEL.

[Ill.u.s.tration: Fig. 254. The Small Tower.]

[Ill.u.s.tration: Fig. 255. The Hub.]

We were now ready to make the wheel. From Lumberville four 1/2-inch boards, each 3 inches wide and 15 feet long, were procured; also a bar of iron 3/4 of an inch in diameter and 2 feet long. At the center of one of the boards a block of wood 4 inches long and 4 inches in diameter was nailed on for a hub. A 3/4-inch hole was now drilled through this hub and the board. Holes were also drilled into the other boards at their centers. Then they were all strung onto the bar and s.p.a.ced like spokes at equal angles apart. Bill had figured it out some way that the ends of the boards should be just about 5 feet 10-1/2 inches apart. When the boards were all arranged we nailed them together at the center, and connected the ends with narrow tie boards, as indicated in Fig. 256.

THE BUCKETS.

[Ill.u.s.tration: Fig. 256. The Water Wheel.]

Eight large tomato cans were now procured and fastened to the spokes at the ends on the inner side, that is, the side the hub was nailed to. We couldn't very well nail on the cans, so we punched two holes in the side of each can and then secured them to the spokes by pa.s.sing bolts through these holes and the boards.