464 



Mr. J. D. Morgan on Impulsive 



in a simple manner the usual assumption (shared by Camp- 

 bell) that the time during which the voltage acts on the 

 gap after passing the line V decreases as the voltage at 

 which the spark appears increases. Considering the curve 

 «o = 2, then with sufficient initial ionization the sparking 

 voltage is given by V 2 . If the initial ionization is diminished 

 the voltage must be maintained for a longer time and 

 the sparking voltage will reach some value higher than V 2 . 

 Likewise with the other values of i the sparking voltages 



are represented by V 3 V 6 . 



Fio-. 1. 





















/ 





-^i Q =6 













<--/ =5 







/ / 



/ / 





"~~"<o=* 





V6 



Ms 





/ = 2 







/ /** 



A X 



^^2^ 





—^ 'o~' 



^0 



A- 









Vo 



The sparking voltage conditions for a given gap as 

 indicated by figure 1 are purely hypothetical. What is 

 there attempted is to associate definitely the rate of rise of 

 voltage with time, and it has been mentioned that any of the 



