WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. 



257 



on the corona forming rod, is obtained from the measured value 

 of the voltage and the dimensions of corona rod and outer cylinder 

 B (Fig. 4). As these results were obtained they were plotted, and 

 Fig. 7 shows the resulting relative location of the points. The 

 equations of the straight lines were obtained by a method of 

 analysis proposed by Steinmetz for deriving from a series of ex- 

 perimental values the most probable equation. 



It will be seen that there is a linear relation between E/8 and 

 i/\/Sr, but that there are two such relations resulting in two 



TABLE I. 



Corona Voltage Reading. 



Straight hnes of different slopes, these lines intersecting at the value 



I 



Vs^ 



= 2.3. 



(5) 



In other words the law of corona must be expressed by two equa- 

 tions, one for values of i/\/Br below 2.3, this equation being 



^ Q , 9-93 



(6) 



