On another block of wood fasten two wires, as shown in Fig. 2, so that their ends can be placed in the holes in the first block. Then connect up with the motor and battery as in Fig. 3. When the block is placed on with the big arrow A pointing in the direction indicated in Fig. 3, the current flows with the small arrows. To reverse turn through an angle of 90 degrees (Fig. 4).
Contributed by F. Crawford Curry, Brockville, Ontario, Canada.
Alarm Clock to Pull up Furnace Draft
Automatic Time Draft-Opener
A stout cord, A, is attached to the draft B of the furnace, run through a pulley, C, in the ceiling and has a window weight, D, attached at the other end. A small stick is put through a loop in the cord at about the level of the table top on which the alarm clock F stands. The other end of stick E is placed under the key G of the alarm clock. When the alarm rings in the early morning, the key turns, the stick falls away, releasing the weight, which pulls the draft open.
Contributed by Edward Whitney, 18 Gorham St., Madison, Wis.