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 tlie 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. 



