684 Prof. Fleming and Mr. Richardson on the Effect of an 



The maximum cymometer current = A = 0*1195 ampere 

 without the added resistance in circuit, and the maximum 

 current with the added resistance of 7*1 ohms = A 1 = 0*0635. 



From the above observations and curve-measurements we 

 calculate the following Table II. : — 



Table II. 

 1 mm. spark-gap with air-blast on gap. 



Cymometer 



Current as 



per cent, of 



max. current 



= 100 a/A. 



Value of 



Mean Value of 



n 



Value of 



95 

 90 



85 

 80 

 75 

 70 



9-58 

 6-47 

 5-09 

 418 

 3-58 

 3-08 



•0067 

 •0098 

 •0126 

 •0152 

 •0177 

 •0205 



•0643 

 •0635 

 ■0642 

 •0636 

 •0635 

 •0632 







Mean Value of D = -0637 



The values of D obtained from the various measurements 

 of the resonance curves are seen to be in very fair agreement. 

 We then calculate the value of S 2 the cymometer decrement 

 from the formula 



A 2 DS 2 =» Af(D + 0-0258)(8 3 + 0-0258), 



where A = *1195, Aj = *0635, D = *0637, and hence 

 S 2 = *017 = decrement of cymometer including that due to 

 the resistance of thermoj unction wire. 



Hence S 1 =:X)-S 2 = -0637-*017 = *0467. 



Accordingly the total high frequency resistance of the 



. .. ^ 4NLA , T . ± , : . , ± 

 primary circuit = It = — 1 9 , where L ± is the inductance 



= 5012 cms. and N is the natural frequency =1*25 x 10 6 . 

 Hence we have 11 = 1*17 ohms, and since the high frequency 

 copper resistance of the rectangular circuit =0*31 ohm, we 

 find that the spark-gap resistance for this 1 mm. spark is 

 0*86 ohm. 



Observations made with 2 mm. and 3 mm. spark-gaps with 

 air-blast in each case gave results of which the final calcula- 

 tions and measurements are embodied in Tables III. and IV." 



