305 



A Simple Method of Harmonizing Leyden Jar 

 Discharges. 



Arthur L. Foley, Head of the Department of Physics, Indiana University. 



Publication No. Jf.1. 



Jn the photography of sound waves 1 one of the chief difficulties is to secure 

 the proper time interval between the sound producing spark and the illum- 

 inating spark which pictures the wave. A spark gap is always apparently 

 more or less erratic. When one places two gaps in series. Figure 1, and en- 



ELECTRIC MACHINE TERKI1 



THEOPETICAL CROSS-SECTION OF SOUND WAVE, EXPLAINING FORMATION OF WAVE SHADOW ON I - - 

 I :il ENDS OF WAVE PRODUCE BUT LITTLE EFFECT ON LIGHT PASSING TO PLATE. 

 ■\1% TOWARD THE CENTER. THUS GIVING AH OUTER OARK RING -: 

 L.R.. WHERE RE^SACTEO AND HON DEVIATED RATS *RE SUPERPOSED. 



deavors to adjust the condenser C to make the spark L. occur at a definite 

 time after the spark S, he finds that the time interval is far from constant. 

 The interval varies, not merely because of variations in the spark gaps them- 

 selves, but because of the charge remaining in the capacity C after a spark 



1 A New Method of Photographing Sound Waves. Physical Review. Vol, XXXV. 

 No. 5, November, 1912. 



5084 — 20 



