88 Prof. Chattoek, Miss Walker, and Mr. Dixon on the 



Now, if they are formed in the gas, the process may be 

 expected to occur chiefly in the strong field near the point, 

 in which case it is practically equivalent to lengthening the 

 discharging point; that is to adding a more or less constant 

 quantity to the values of z of from 8 to 13 millimetres. That 

 this has not occurred seems to follow from Curves II., the 







urves 



II. 



'W02 



o-oi 



D-00 





















i 





















/ 





Hyl 



) /?OG£ 



7V 

















3-2 A 



'/C/?0 A 



MPS. 

























+ 





















/ 





















/ 



















/ 









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V 



















/ 





















/ 



s 



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' 















/ 



s. 



' 



i 



i 









1 / 



\// 



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, 



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1 



1 1~~^~ 







\ 



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\£S k 







1 



i 



3 4 5 6 



Centimetres (z). 



pressure-distance curves for hydrogen. In these each nega- 

 tive point is the mean of ten, and each positive of four 

 observations. The positives (full curve) were not sandwiched 

 with the negatives (dotted curve) as usual, in order to obtain 

 greater constancy in the negatives. There is a bend in each 

 curve near z= 1*2 centimetre, due no doubt to the shifting of 

 the region where the current enters ihe ring from the front 

 to the inner surface of the latter as the point approaches. It 

 will be seen that these bends are vertically over one another ; 

 also that the pressure vanishes at about the same value of z 



