Page:Popular Science Monthly Volume 88.djvu/967

 Popular Science Monthly

��939

��For Those Midnight Serenaders

SOME people live in neighborhoods that are very popular with cats. The fence is the back-yard band stand, where cats of all sizes and vocal abilities assemble and give voice to their woes just as one is preparing to go to sleep. After ineffectively following the accepted plan of hurling shoes, hair-brushes and other missiles at the disturbers, one sufferer decided to solve the problem with the aid of electricity. The plan has worked admirably.

The fence was made of boards sepa- rated about one quarter of an inch. Along the tops of these boards he nailed short strips of brass and connected them alternately to the terminals of a small induction coil which had been discarded from an automobile. When the mid- night serenaders trod upon these alter- nate strips, their musical inspiration departed completely, and they them- selves followed it swiftly, but quietly. Of course it was necessary to have the coil turned on all night, although the inventor plans to install a clock-work regulator made from an old alarm clock, so that the coil will have to work only

���IMIS wmt RUNS ON.ONt SlOt Of THE FENCE -

��COfPER STRIPS ON lOP Of FENCE

��tHIS WIRE RUNS ON ONE SIDE Of THE FENCf^

��INDUCTION COIL-

��'S

��^\W

��Would that wc could apply this principle

to the back-yard band and also to the

organ grinder!

���The number of sections cut out of the

brass disk determines the number of

flashes produced

during those hours when the night Is most hideous. He expects that, in time, the cats will be wise enough to pass the word along to leave his back fence alone.

Making a Simple but Efficient Flasher

A FLASHER for low voltage lamps can be made in the following manner: Remove the hands, including the second hand, and the glass from an old clock. Make a small brass disk (this can be done on a lathe), with a hole in the center just large enough to fit snugly on the axle of the second hand. Divide the disk into four parts, and describe a concentric circle, as shown in the diagram. File out two pieces along these lines, as indicated in the diagram. After replacing the second hand and the disk, fasten the clock to a board.

Two brushes can be made from an old clock-spring, after taking the temper out by heating. Screw them to the board in such a position that they touch the wheel lightly. This arrange- ment and also the connections with lanii)s and battery are shown in the diagram.

If more flashes are wanted, a greater number of sections can be cut out of the disk. Many different combinations can be produced. Instead of ordinary white bulbs, colored ones can be used, adding greatly to the effect. — Josiii'ii Kraus, Jr.

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