It is so simple that
the cuts scarcely need explanation. In Fig. 1 is seen the sending
apparatus, consisting of a 40-cell battery connected with two
copper plates 36 by 36 by 1/8 in. The plates are separated 6 in.
by a piece of hard rubber at each end.
In Fig. 2 are seen duplicates of these insulated plates, connected
with an ordinary telephone receiver. With this receiver I can hear
distinctly the electric signals made by closing and opening the
Morse key in Fig. 1, and I believe that in a short time I shall be
able to perfect this system so as to send wireless messages over
long distances.
--Contributed by Dudley H. Cohen, New York.
** Stop Crawling Water Colors [54]
To prevent water colors from crawling, add a few drops of ammonia
or lime water, or a solution of sal soda.
** Small Electrical Hydrogen Generator [54]
A small hydrogen generator may be made from a fruit jar, A (see
sketch), with two tubes, B and C, soldered in the top. The plates
E can be made of tin or galvanized iron, and should be separated
about 1/8 in. by small pieces of wood. One of these plates is
connected to metal top, and the wire from the other passes through
the tube B, which is filled with melted rosin or wax, to make it
airtight.
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