March, 191S] A Lecher System — Experimental 149 



Neglecting momentarily the influence of oscillator deteriora- 

 tion, the only way in which the third and fourth variables could 

 be studied was to get for every new length of oscillator both 

 bridge and spark-gap curves for every peak ; all this for a given //. 

 And then for a new value of // we had to repeat all the above 

 operations. Table I shows the various values of y used. 

 It also shows the longest and shortest oscillator lengths, the 

 length of the Lecher wires and of the receiver. As heretofore 

 these lengths are the straight-away lengths, GH, LM, NT, 

 Figure I. 



III. Summary Curves and Tables for Variable y. 



Proceeding in the manner indicated above and plotting 

 all bridge and spark-gap curves we obtained summarizing 

 curves of intensity such as we have shown in Figure 3. They 

 were obtained by tabulating the peaks of the spark-gap curves 

 for different oscillator lengths. 



It is plain from an inspection of Figure 3 that the higher 

 tones are proportionately greater the smaller the y is, a thing 

 Blake and Sheard found. For the curves for the values of y 

 shown in the figure up to and including 30.4 cm., the funda- 

 mental was taken with the bridge at 150. But for values of y 

 greater than 15 cm. the fundamental splits up into two peaks 

 as the curves of Figure 4 clearly show (see also Curve II, 

 Figure 5). Consequently in Figure 3 for y = 18.2 cm. and 

 30.4 cm., the relative intensity of the fundamental is too low. 

 A further study of Figure 3 shows also that as y increases the 

 length of oscillator for maximum resonance increases. Our 

 results on this matter are summarized in Curves III, Figure 5. 

 For harmonics above the third the intensity is so low for the 

 larger values of y that one is not able to examine how the 

 optimum oscillator length varies. For the fifths the optimum 

 oscillator length for y = l8 is unquestionably somewhat longer 

 than for t/ = 12, but the variation is proportionately less than 

 for the thirds and fundamental. 



