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The Ohio Journal of Science [Vol. XVIII, No. 5, 



the frequency numbers in general, reaches a minimum for the 

 third harmonic, and rises again for the fundamental. Curve 

 V shows that the optimum spark-gap length for the funda- 

 mental increases with increasing 7/ in a linear ratio. This is 

 probably true for the higher tones also, though the variation 

 is so little outside of the limits of experimental error that it 

 would be difficult to show this for the higher tones. Curves 

 IV and V show the absolute need for taking spark-gap curves if 

 the tone intensities are to be compared. 



Figure 6. 



To eliminate the various curves discussed above and to get 

 at a common basis for comparison of the various sets of curves 

 for the different values of y we proceeded as follows. Starting 

 with a given oscillator length GH, and a given total length GT 

 of the system. Figure 1, the value of y was changed from large 

 to small values by steps in as short a time as possible. For 

 each y we located the fundamental peak or peaks and then took 

 spark-gap curves. In this way Curve I of Figure 5 was obtained. 

 The curve is extrapolated to zero for y^b cm., for at this distance 



