IN the days of melting snows and frequent showers there are plenty of places where a boy can rig up a fine water wheel which can be made of cigar-box wood and which will give considerable power. The drawings show an undershot wheel, but if there is enough height of water from the dam, you can get more power with an overshot wheel, where the water falls on the wheel from above. Ordinarily, however, the undershot is the better.

The dam is simply a big board with a square hole at the center for the water to run through. Other parts of the device include a trough with a frame fastened to it to support a water wheel, and a paddle wheel with buckets or paddles to catch the water.

The trough T is fastened to the dam board D opposite the hole 0, so that all the water running through this hole follows the trough. As the water rushes down, it strikes the blades b of the wheel W and by its force against them turns the wheel.

The board for the dam has the hole near its center so that the lower part can be buried in the ground to prevent the water leaking underneath. The hole, however, is left a little above the ground, so that as great a head of water as possible can pile up against the other side. If water is running in the gutter to a depth of several inches, the dam can be omitted, and the trough merely buried, so that all the gutter water will have to flow through it.

The trough T for a good-sized wheel is made from a cigar box with the top and ends knocked off. The end is nailed to the board dam as in the lower sketch and may be fastened with a block underneath if necessary. The wheel is made of two circles of cigar-box wood with six or eight paddles between.

For this, first cut out the circles, marking them carefully with a compass, then dividing them into, say, six parts, if the wheel is small. Cut six paddles, a couple of inches wide and a little shorter than the width of the trough inside, and nail these around the inside,- the outer edge at the edge of the circle and all pointing in toward the center of the wheel. This can be seen in the upper sketch at the right. The wooden disk or wheel is shown at W and the paddle pieces at b.

When these are nailed in place, the second round piece W is put on, and brads are driven through it into the ends of the paddles b, fastening it. Be sure when you do this to space the paddles evenly, as on the first circle.

The axle is a round stick of wood about half an inch in diameter and an inch longer than the trough is wide. One end pivots on a nail N in the center of the end, this nail running loosely through a hole in the upright E nailed to the side of the trough.

On the other side the shaft is supported by the upright F with a half round part cut at the top into which the axle fits. Over the top a loop of tin C is caught and held on either side by brads or small screws. This is shown in the big drawing as well. This end should fit loosely, for when it gets wet it will swell and stick, if ample room is not left.

If care is taken, the wheel can be made very neatly in this fashion, and it should then be painted or dipped in paraffin to prevent warping. The dam, trough, etc., can also be painted to suit the taste. The grooves for the pulley cord can be cut in the axle direct, as shown, or a larger pulley can be fastened on if you want more speed to the belt. This is a toy that any boy can make.