Fig. 510
Fig. 510 shows how high tide can be represented by means of boxes and cardboard; D, E, F are boxes which form a quay into which the car runs. A, B, C are pieces of cardboard resting on pieces of stripwood glued to boxes D, E, F, and similar boxes on the other side, or the cardboard can rest on boxes. If boxes cannot be found big enough for D, E and F, several boxes can be built up. Slots a b and c d must be left wide enough for the supports to pass freely, and the threads must be omitted at front and back. The rails must lie exactly under slots a b and c d. The pieces of cardboard A, B and C should be coloured blue. The thread from the car underneath the "water" can pass into box F and up through a hole in the top, where the winding gear can be placed, but, of course, it can be worked from below. Sheets of cardboard A and C can be surrounded by boxes or fastened in a large box, or have cardboard walls built around it.
Tower Bridge. A very simple and effective model of Tower Bridge can be made, which will prove a delightful plaything.
The measurements given in this chapter need not be followed, but the bridge can be made larger or smaller according to taste. The whole structure can be of wood or of wood and cardboard.
Two small boxes are required, made of wood ¼ inch thick, about 4 inches in length, breadth and height. (If such small boxes cannot be found they must be made.)
Take off one side of box, A B C D in Fig. 511, which shows the mechanism of the toy. Into the edges D F and C E screw two small screw-eyes, G and H, about ¼ inch from the top.
Fig. 511
Now cut a piece of wood 8¼ inches long for the bridge. The width of bridge a b must be equal to width of interior of box. For the present model it will be 3½ inches.
The wood used for the bridge should be about 1/8 inch thick.