Clap! Let There Be Light 



Ey clapping your hands you can light up the whole 

 house. No, there is no microphone to hear the sound 



SUPPOSE that you wished to light 

 the electric light in the library while 

 you were in the living-room and that 

 you could do so by the clap of your 

 hands. Or, on coming home at night, sup- 

 pose that you 



Armature Stop Pendulum^ contacts on inter 



dient and refuse to come out of its kennel, 

 because of the variable current changes 

 of the microphone mechanism, by which 

 it was operated. The new means which 

 Mr. Berger has invented to make the dog 



obey every 



Ratctiet Magnet 



Noise of hand- 

 clap jars a 

 small pendu- 

 lum away from 

 diaphragm 

 and breaks the 

 relay circuit 



Point of contact 



could light 

 your way by 

 the same 

 means with- 

 out hunting 

 for the elec- 

 t r i c light 

 switches in 

 the dark. 



But what's 

 the use of sup- 

 posing? Mr. 

 H. Christian 

 Berger, a New 

 York city in- 

 ventor, has made all such things 

 possible by inventing a new con- 

 trivance which he calls a sound- 

 operated circuit controller. Besides the 

 utilitarian uses to -vVhich the device may 

 be put, it may be employed for the opera- 

 tion of mechanical toys of various sorts, 

 including elec- 

 tric railway 

 trains, electric 

 boats, hoisting 

 derricks, or even 

 the docile little 

 wooden pup who 

 jumps out of his 

 kennel at your 

 hand-clap com- 

 mand — a toy 

 first described in 

 the November, 

 19H), issue of 

 theP0PULARS<'i- 

 ENCE Monthly. 



While the 

 mechanical pup, 

 just mentioned, 

 worked fairly 

 well, on occa- ^,^^^^j^ ^^5,^^^^ ^^^ ^,^ 



Sions it would Introduction of a contrivance 



become disobe- like this one adds novelty 



Sound -operated circuit.controller 



command 

 without fail, 

 is based on an 

 entirely new 

 principle and 

 one wholly 

 different from 

 that of the 

 microphone. 

 While the lat- 

 ter acts by 

 varying the 

 electric resist- 

 ance and cur- 

 rent in a cir- 

 c u i t by 

 changes of 

 pressure and 

 conductivity as a result of the action of 

 sound waves — and does not break* the 

 circuit — the sound-oper- 

 ated circuit controller ac- 

 tually does open the cir- 

 cuit. These circuit breaks 

 are made possible 

 because two con- 

 tacting members 

 are used. . A 

 diaphragm 

 member con- 

 tacting with a 

 pendulum 

 member un- 

 der such 



The apparatus 

 is small. It is 

 but little 

 larger than a 

 lamp socket 



20 



