Surface of large Curvature. 



177 



were used, or the discs were dispensed with, exact propor- 

 tionality no longer holds. 



A series of observations illustrating this proportionality are 

 given 







Table I. 









Yalues of the quotient. 



Current. 



Wire length. 



Potentials. 



L= 31 cm 



L -. 25 cm . 



L = 15 cm . 



L = 10 cm 



14 



16-7 



157 



17:3 



16-0 



16 



36-1 



35-4 



36-6 



34- 



18 



60-6 



59-3 



60-6 



60- 



20 



90'0 



90-2 



92-6 



88- 



22 



120- 



118-2 



122* 



120' 



24 







160- 



162- 



163- 



26 









214- 



216* 



Diameter of cylinder, 



9-4 cm . Diameter of wire, 0'0047 cm 



4. The relation holding between the applied potential and 

 the resulting discharge current is found to be expressed by the 

 quadratic : 



I = aLV(V-6) 



I, Y, and L, having the usual significance, and a and b are 

 constants, depending upon the cylinder, wire, and gas. The 

 constant b is found to approximate, more or less closely, to the 

 " minimum-potential " of Rontgen, i. e., the least potential 

 which will give the measureable discharge. 



This law was found applicable for cylinders of diameters, 

 from 2 to 10 cm , giving agreement within errors of observation, 

 except for potentials which differed only very slightly from 

 the " minimum potential." Even after the gas had been used 

 for a considerable time without renewal and also at widely 

 varying pressures (from 20 to 80 cm of mercury) the relation 

 between current and potential remains similar, with, naturally, 

 different constants. As illustration I cite a series, taken at 

 random from the considerable number of observations made : 









Table II. 







Y 







I 



V 





I 



(arbitrary 



units.) 



(calc.) 



(observ.) 



(of cylinder. 



(calc.) 



(obs.) 



13 





13-7 



17'0 



—14 



15*3 



17- 



14 





26'5 



27' 



— 16 



36*2 



36' 



16 





56" 



55- 



— 18 



62- 



61- 



18 





92- 



92- 



—20 



92- 



92- 



20 





135* 



138* 



—22 



126- 



122- 



22 





184- 



186* 



— 24 



166* 



162- 



24 





240- 



240- 



—26 



210* 



206' 



26 





313- 



320' 



— 28 



260' 



257* 



a - 



= -543 



; &== 



11-7. 



— 30 



a = 



313' 

 •389 ; b = 



315- 

 12']5. 



