The Scientific American Boy Part 22

It was rather a crude pump, but it did all the work we required of it.

As the wheel went around the crank shaft would move the piston up and down. Whenever the piston went down, the air in the pipe would press up the edges of the leather disk and squeeze past (see Fig. 295). Then when the piston came up again, the leather disk, being backed by the wooden disk beneath it, was kept flat, so that no air could force its way back into the pipe. This made a partial vacuum in the pipe, and the water from the well rushed up through the valve at the bottom to fill it (see Fig. 296). When next the piston went down the bottom valve closed and more air forced its way past the piston. Then on the next upward stroke more water flowed into the pipe, until, after a number of strokes, all the air was pumped out and the water which took its place began to force its way up past the piston and eventually to flow out of the spout into the cask.

Our old windmill was sold to a farmer near Lumberville when we broke camp that fall. We carted it over and set it up for him. A number of years later I saw it still faithfully at work pumping water for his cattle. The original pump had been worn out and a new one subst.i.tuted, but otherwise the old windmill remained just as we had first rigged it up.

[Ill.u.s.tration: Fig. 295. Fig. 296. Action of the Pump.]

CHAPTER XXIV.

THE GRAVITY RAILROAD.

"About all we lack now," said Dutchy, when the windmill had been completed, "is a railroad."

"Then suppose we build one," was Bill's unexpected rejoinder.

We all thought he was joking, but he wasn't.

"I don't mean a steam railroad," he said, "but a gravity railroad."

"A what?"

"A gravity railroad. Oh, you know what that is--a roller toboggan--the kind they have down at Coney Island." And he went on to explain how we could rig up a simple roller toboggan on our island.

His plan was to build an inclined trestle on the high ground just below the lagoon, and then run wooden tracks along the sh.o.r.e down to the pontoon bridge, and across the mill-race to Kite Island. We started first to dig a road down to the bridge, because the bank was quite high at this point. The task was rather greater than we antic.i.p.ated, but we kept steadily at it until we had cut a fairly good road through the bank, though the grade was rather steep.

Before proceeding with the trestle and track we thought the best plan would be to build our car, and then we could use it as a gauge to determine how far apart the rails should be set.

THE CAR.

[Ill.u.s.tration: Fig. 297. Putting the Car Body Together.]

First we got a 2 x 4-inch scantling, and cut from it two lengths, each 4 feet 6 inches long. These were laid on edge just 30 inches apart, and then a number of boards were nailed across from one scantling to the other and sawed off flush with their edges. The floor thus formed was now turned over so that the scantlings lay uppermost and the sides of the car were then nailed on with their edges overlapping the ends of the floor boards. The sides, which were about 18 inches high, were each made of two boards firmly battened together. Great care was taken to securely nail both the flooring and the sides to the scantlings, because these scantlings were to carry the wheels of the car. The car body was completed by nailing on the end pieces which overlapped both the flooring and the side walls.

THE f.l.a.n.g.eD WHEELS.

[Ill.u.s.tration: Fig. 298. The Car Wheel.]

Next we sawed out the wheels of our car. From a board of hardwood 3/4 of an inch thick four disks, 12 inches in diameter, were sawed out. Then from a board 1 inch thick four 9-inch disks were sawed out. We cut these disks in the same way as we had made the disks for our surveying rod (see page 78), by making cuts across corners and finally smoothing off the angles with a draw-knife. A half-inch hole was now drilled in the center of each disk. Then on each large disk a smaller one was placed, with the center holes of the two coinciding and the grain of one lying across the grain of the other. In this position they were firmly nailed together, making a wheel like those used on a railway car, with the small disc forming the tread of the wheel and the large disk serving as a f.l.a.n.g.e.

THE CAR AXLES.

[Ill.u.s.tration: Fig. 299. Car Body with Axles in Place.]

For the car axles we bought four 1/2-inch bolts, 6 inches long, with two washers and two nuts for each bolt. In each side of the car, about 8 inches from the ends, we nailed face blocks; that is, blocks of wood for the wheels to bear against. These face blocks were only 1/2 inch thick.

Then in these blocks holes were drilled which were carried clear through the scantling. The holes were just large enough for the bolts to fit snugly in them. The bolts were inserted from the inside, so that their threaded ends projected out at each side of the car. A patch of wood was nailed to the scantling over each bolt head to prevent the bolt from slipping back into the car. Then the wheels were mounted on these bolts, which served as axles.

MOUNTING THE WHEELS.

[Ill.u.s.tration: Fig. 300. Section Showing How to Fasten on the Wheel.]

First a washer was placed on the axle, then the wheel was applied, with the larger or f.l.a.n.g.e disk against the face block, after which another washer was slipped on. A nut was screwed against this washer just tightly enough to keep the wheel snugly in place, and yet let it turn freely on its axle. Then to keep this nut from shaking loose a second nut was screwed on against it. While one fellow held the first nut from turning, another screwed the second nut against it as tightly as he could. The second nut is technically known as a "jam nut," or "lock nut." The car was completed by laying a couple of boards across from one scantling to the other to serve as seats.

THE RAILWAY TRACK.

[Ill.u.s.tration: Fig. 301. The Inclined Trestle.]

[Ill.u.s.tration: Fig. 302. Joints of the Track.]

The trestle was now begun. First we erected a level platform, which was to be the starting point of the railway. This was made very substantial by planting the corner posts firmly in the ground and then bracing them together with diagonal braces. A couple of planks leaning against the platform at one side provided a convenient means for mounting to the top. From the platform the trestle ran down at an easy incline to the ground. It was made of 2 x 4-inch scantlings supported at intervals on posts driven into the ground. The opposite posts were firmly braced with boards fastened diagonally across them. The scantlings were to serve as rails, and so we fastened them at the proper distance apart with ties nailed to the under side. But to be sure that the rails were not too far apart or too close together, the car was rolled over the track and the rails were set to keep the tread disks of the wheels on them and the f.l.a.n.g.e disks just clear of their inner edges. The ends of the rails were cut off at an angle, making a slanting joint, as shown in Figs. 301 and 302. They were fastened firmly together by nailing a piece of board on the bottom and also on the outer side.

THE CARPENTER'S MITER BOX.

[Ill.u.s.tration: Fig. 303. Carpenter's Miter Box.]

To make sure that the ends were all cut to the same angle, we made a carpenter's "miter box." Two sideboards were nailed to a baseboard, making a trough large enough for the scantling to be set in it. Then we sawed through the sides of the trough at an angle of 45 degrees. When we wanted to cut the end of the scantling at an angle it was placed in the trough, and with the saw set in the saw cuts, as a guide, we were sure that they would all be cut at the same angle.

LAYING THE TRACK.

[Ill.u.s.tration: Fig. 304. How the Track was Anch.o.r.ed.]

From the bottom of the inclined trestleway we continued the track down the slope to the river; but for the sake of economy, instead of using 2 x 4-inch scantlings for the rails, we bought a number of 2-inch planks at Lumberville, and had them sawed up into strips 2 inches wide. These 2-inch square rails were fastened together with slabs nailed on at frequent intervals. To maintain the proper gauge the car was rolled over each pair of rails, which were nailed first at the ends and center. To anchor the track we drove short posts into the ground so that their upper ends lay flush with the surface. A post was provided under each joint and one under the center of each rail, and then the slab ties were nailed securely to these posts. In imitation of a full-sized railway, we made it a point to "break joints" on our track; that is, to make the end of one rail come in line with the center of the opposite rail, as shown in Fig. 302. Our track was continued across the pontoon bridge and ran around the west sh.o.r.e of Kite Island. The track was straight as far as the sh.o.r.e of Kite Island, whence, by an easy curve, it was carried around to the log cabin.

THE FIRST RAILWAY ACCIDENT.

Dutchy was the first one to try the railway. He sneaked back to the platform while the rest of us were putting a few last touches on the track. The first we knew the car came tearing down the track at full speed, with Dutchy yelling at the top of his voice for us to get out of his way. Bill was on the bridge when the car came along and he had no time to run for sh.o.r.e, but with great presence of mind he jumped into the water and clung to one of the barrels. But the joke of it all was that Dutchy himself got a wetting too. The track at the middle of the bridge was not quite true to gauge. It was this very spot that Bill was fixing up when Dutchy came along. The end of a rail was bent in far enough to catch the f.l.a.n.g.e of one of the car wheels, and in a moment Dutchy, car and all, was slung head over heels into the mill-race.

Fortunately no serious harm was done. Dutchy landed a little ways down-stream, and Reddy, by quick work, managed to rescue the car just as it was floating off under the suspension bridge. The car was undamaged except that the f.l.a.n.g.e of a wheel was split off.

Of course, Bill was as mad as a hornet at Dutchy, and expressed his feelings in no mild terms. But his anger was somewhat tempered by the fact that Dutchy received as bad a punishment as he had inflicted.

[Ill.u.s.tration: The Start of the Gravity Railroad.]

TESTING THE TRACK.

We had to cut a new f.l.a.n.g.e disk for the broken wheel, and to prevent the f.l.a.n.g.es from splitting off again we nailed a batten across the inner face of each wheel extending down to the very edge of the f.l.a.n.g.e disk.

This batten was fastened on across the grain. When everything was completed the car was started down the track empty to see if it would keep the rails. It went beautifully as far as the bridge, but was too light to run much beyond. The next time we loaded it up with stones and had the pleasure of watching it sail down hill, across the bridge and vanish out of sight around the sh.o.r.e of Kite Island. That was demonstration enough. We knew it would carry us safely and it did. The next time we tried it four of us piled into the small car, and in a moment we were off on a most thrilling ride, which ended right in front of the log cabin, where the car came to a sudden stop after riding off the end of the rails and plowing through the sand for a short s.p.a.ce.