Field on the Discharge through a Gas. 373 



transverse and longitudinal effects are therefore of a different 

 nature. 



The dependence of the fall in voltage on the strength of 

 the held when the pressure in the tube is kept constant, can 

 bo seen from the following 

 pressure was *052 mm. 



series of readings. 



The gas- 





Per cent, decrease in volts 



V leld. 



caused by field. 



L59 



1-1 



238 



32 



318 



4-3 



39S 



6-5 



477 



7-1 



589 



8-7 



(585 



10-6 



sU 



13-i) 



1050 



138 



These numbers are shown graphically in tig. 1. The effect 

 reaches a limiting value in this case ; in others it reached a 

 maximum, and then slightly decreased as the field continually 

 increased ; this usually took place in the wider tubes. 



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f/£t.O 



The fall in volts docs not increase indefinitely as the 

 pressure is decreased. In all the cases tried, it appeared 

 either to reach a limiting value or much more generally to 

 fall off. and in some cases, at the lowest pressures reached, 



