Now on winding up the spring and pressing down the lever the works will start into motion and the sails will revolve. The speed can be regulated by placing the sails at such an angle that they will offer more or less resistance to the air.
The slot in the door for the insertion of the penny must be cut three-quarters of an inch below the upper edge of the wooden partition, and inside you must fasten a tin trough to conduct the penny to the scoop at the end of the lever. This trough must slope downwards to the edge of the scoop, or the penny will not fall into it, but remain just inside the hole.
The model is now complete, and works as follows: The spring having been wound up and the door closed, the works are kept from moving by the hook of the lever catching in the notch of the pulley, but on a penny being put into the hole, and sliding into the scoop at the other end of the lever, its weight presses down the scoop end and lifts the hooked end out of the notch in the pulley, which turns round, and continues to do so, carrying the sails of the mill round with it till the notch again comes under the hook, which (the penny having fallen out of the scoop into the drawer) falls into it and stops the machinery, giving one revolution of the pulley for a penny. The pulley being twelve times larger than the spindle of the sails, these will revolve twelve times each time the model is started. The model will work about 204 times each time it is wound up.
Having finished the windmill to your satisfaction, we will now turn our attention to the construction of a model requiring rather more complex machinery. This is shown at Fig. 4, and represents a cutter-yacht sailing on the port tack, on a lee shore; which, if carefully made, so as to produce the effect of the rolling and pitching of a real yacht upon a real sea, will catch many a penny.
The case is made exactly in the same manner as the former one, and has the same dimensions, but has no horizontal partition, only a cross-piece in the front, half an inch square.
The inside of the back you must paint to represent a cliff and sky, or you can paste a coloured picture of the same on it.
The yacht is to be 5 in. long, and is to be set in a sea of silk, which will be described further on. If you prefer it, a full-rigged ship can be substituted for the yacht. For the machinery you will require, as before, an eight-day clock movement, some brass wire, and three or four pulley-wheels. Fig. 5 shows the front view of the mechanism when complete, and Fig. 6 the end view of the same.