Fig. 449
Fig. 450
Fig. 451
Fig. 452
F is the flange for fastening it together, and E, D, C, B are flanges for fastening it to roof A B E F (Fig. 448). A round hole is filed out at A, after the reservoir is fastened together, through which the sand runs. The wooden side of box, A B E F, is taken off and a piece of cardboard is nailed to the box instead. This can have a hole cut in it, K in Fig. 448, and the reservoir glued under it. G H is a bar of stripwood nailed across the front of the box, through which a hole, N, is bored. The axle of the wheel passes through this and through a corresponding hole in the back of the box. As the sand runs out of the reservoir, it falls into the boxes and so turns the wheel; hence the sails of a windmill, the hands of a clock, etc., fastened to axle, L M, can be made to turn. Notice carefully that the hole at the bottom of the reservoir should be over the centre of the boxes of the sand-wheel and a little to one side of the wheel, as in Fig. 448. Part of the back of the box, P Q R O, should be cut out to allow a tray to go in to receive the sand.
