I GOT the inspiration for this toy from seeing a patent plate washer in a photographer's shop, and the mechanical movement was so interesting that I went to work and made a toy to work on the same principle.

This toy works by a stream of water, and I. have shown it set up with a dam in the gutter so that the water overflowing will rock the toy. This rocking works the rod D back and forth, and you can fasten a saw or any light machinery, like a small pump, to this arm and move it by the power of the rocking.

The principle on which it runs is as follows:

First the box B is made water-tight, with a high partition in its center at P. This box rocks on a bearing n.

Above is the spout or pipe T from which the water runs. As the water comes out of the pipe, it runs into the high side of the box and fills it with water, which makes it heavier than the low side, and the high side drops.

This rocking over of the box brings the partition P on the other side of the stream of water, so that now the other side fills until that too is heavier than the low side and the box rocks back. Thus as long as the water runs, the box will rock. To empty the water on the low side, a valve V is fixed in each side, like the air valve in the siren whistle described in another chapter, only a nail is driven into the valve V, so when a side drops, the nail hits the board below the box and opens the valve, thus letting the water on the low side run out. When this side rises, the valve closes of its own weight.

The rocker box in the figure is made of a cigar box with a cigar-box wood partition at P. It can be made of two boxes with a tin piece for the partition as in Figure 5.

Figure 4 shows the bearing. This is made by nailing a pointed piece of wood, point down, to the side of the box at the center, and pivoting it on the nail shown driven through the hole in the triangular piece into a wooden crosspiece beneath, running under the box between the upright triangular pieces. The wooden crosspiece beneath is shown nailed to the board beneath the rocker.

This board is the bottom of a cracker box rigged up for the dam as in Figure I, which shows the bearing nail at n and the triangular piece at b.

The pipe T runs through a hole in the box at the proper height just above the partition. The box is buried in the dirt to stop the gutter water which must then run through the pipe.

Figure 2 shows how the valve is made of a piece of soft leather L, a piece of wood v to fasten one edge to the bottom of the rocker box over a hole 0, and a wooden stiffener V.

A nail N through the leather into V serves to open the valve when it hits as the box goes down.

This toy can be made to work in the sink by using the water from the tap.