Fig 2
Make the circular frames out of a wooden circular box—such as a tooth-powder box—about four inches in diameter. Take off the lid and cut away the rim that it fits on, and saw the box into rings about a quarter of an inch wide, marking the box first with a pencil, and cutting through the marks with a fine saw (as [Fig. 2]). Have your circular glasses cut the exact size of the inside of these rings. Fix the glass in each ring so that the wood projects a trifle beyond the glass on one side. With a three-cornered file cut a triangular groove all round each ring about one-sixteenth of an inch deep.
Fig 3
Fig 4
Fig 5
Make the small wheel out of a cotton-reel about an inch or an inch and a quarter in diameter. Cut off the ends and cut the other part into slices a quarter of an inch wide, and cut a groove about an eighth of an inch deep all round each (as [Fig. 3]). On one side of each of these pieces fix a short wire about three-quarters of an inch long near the edge; this wire will serve as a handle to turn the wheel by. Fasten this small wheel to the board by a screw that fits easily into the hole in the centre, without too much play ([Fig. 4]). Put the circular glass and frame in its place and glue a piece of wood (A, [Fig. 4]), about two inches wide and a quarter of an inch thick, to the wooden half of frame. Get two small glass beads about a quarter of an inch long and an eighth of an inch wide. Put a wire about an inch long through each, and bend the wires as in [Fig. 5]. Sharpen the ends and press them into the edge of the wood (A, [Fig. 4], B B), so that the beads will turn easily without touching the wood. Cut away a semicircular portion of the end of the frame ([Fig. 4]) and fasten a small button made of brass plate in it, and fasten another button to the wood (A). These buttons will keep the circular frame in its place. Connect the two wheels with a piece of strong twine, not too thick, going round them both, and fasten the ends by lapping them and sewing them together. Now if you turn the small wheel the large circular frame will turn round in the same direction if your work is well done. The edge of the circular frame must not touch anything but the glass it rests on, the two beads, and the two buttons. The view is painted on the inside of the fixed glass, and the revolving portion is painted on the under side of the circular glass. In [Fig. 4] the mill and background are painted on the fixed glass, and the sails on the movable one.