--Contributed by Louis Lauderbach, Newark, N.J.
** Callers' Approach Alarm [87]
This alarm rings so that callers approaching the door may be seen
before they ring the bell and one can exercise his pleasure about
admitting them.
If one has a wooden walk, the alarm is easy to fix up. Take up
about 5 ft. of the walk and nail it together so as to make a
trapdoor that will work easily. Place a small spring under one end
to hold it up about 1/4 in. (A, Fig. 2). Nail a strip of tin along
the under side of the trap near the spring and fasten another
strip on the baseboard, so that they will not touch, save when a
weight is on the trap. Connect up an electric bell, putting the
batteries and bell anywhere desired, and using rubber-covered
[Illustration: Alarm Rings When Caller Approaches]
wire outside the house, and the alarm is complete.
When a person approaching the house steps on the trap, the bell
will ring and those in the house can see who it is before the door
bell rings.
--Contributed by R. S. Jackson, Minneapolis, Minn.
** Easy Method of Electroplating [88]
Before proceeding to electroplate with copper, silver or other
metal, clean the articles thoroughly, as the least spot of grease
or dirt will prevent
[Illustration: Electroplating Apparatus]
the deposit from adhering.
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