108 



ROYAL SOCIETY OF CANADA 



readings taken are recorded in Table III and curves drawn from them 

 are shown in Fig. VI. From these curves it will be seen that for 350 volts 

 the zero-current pressure in the upper range is 8.23 mm. of mercuiy 

 and for 400 volts 11.1 mms. of mercury. These pressures are practically 





zv.vi.i.'im/s.re.jitxx'ii^L 



the same as those which may be deduced from the experimental curve in 

 Fig. Ill, and it follows therefore tliat tlie method is applicable to the 

 determination of spark potentials in any gas in the range above as well 

 as in that below the critical pressure. 



! TABLE III 



Applied E. M. F. 



Pressure 

 MiUims mercury 



1.8 



2.0 



2.45 



2.77 



3.11 



3.77 



400 volts 



Conductivity 

 Voltmeter 

 indications 



Applied E. M. F. 





 30 

 55 

 50 

 75 

 83 



Pressure 

 Millims 

 mercurv 



2.11 



2.44 



3 



3.22 



4.11 



4.77 



350 volts 



Conductivity 

 Voltmeter 

 indications 





 5 

 10 

 15 

 35 

 45 



