Schmidt, Culebra, Porto Rico, W. I.
** Simple Current Reverser [107]
On a block of hardwood draw a square (Fig. 1) and drill a hole in
each corner of the square. Fill these holes with mercury and
connect them to four binding posts (Fig. 1).
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
[Illustration: Details of Reverser]
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 [107]
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.
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