92 Prof. Chattock, Miss Walker, and Mr. Dixon on the 



to the hydrogen pressures for tube B. II., the pressures being 

 expressed approximately in thousandths of a millimetre of 

 water. As explained above, observations belonging to sepa- 

 rately labelled groups were sandwiched together when made, 

 and the results for the different strengths and signs of dis- 

 charge are therefore comparable. AA and BB have the same 

 meanings as in fig. 3. The dotted line joins the two points N, N. 



The fundamental difference between the positive and nega- 

 tive discharges is very apparent. In the former the dotted 

 line is short and roughly coincides with AA ; in the latter it 

 is longer, and the coincidence is with BB. 



We conclude, therefore, that while the small variations in 

 V + are due to errors of observation and chance alterations in 

 the condition of the hydrogen, the much larger ones in the 

 case of the negative discharge correspond with real changes 

 in V-. 



Fig. 5.— Air. w=1o. B. II. 



Negative. 



A 



\ 





B 







\ 



i/ 









A 



i \. 









J 





A 















p\ ^ 



21 p. 2 





A 

 \ 



/ 



'B 





> 



K 







/ 



/ *^ 



\ 











Microamps 3*2 







A 





/ B 





Pi 21 





\ 



\y 



/ 











A 











B 



/ 



\ 



A 





19 













Pi 29 



Pi 11 





A 

 \ 





/ 









N 



/ 









/ 



\ 







B 



f 

















Pi 15 



15 p< 



0-8 



In figs. 5, 6, 7, and 8 are given the results of similar tests 

 applied, where possible, to the pressures for air, oxygen, and 

 carbon dioxide; as well as a second set, taken by itself, for the 

 negative discharge in hydrogen. The latter is closely in 

 accord with the set in fig. 4, though the variations are not so 



pi 







/ 



B . 



A 



\ 



/ 







/ 



K 







J 



\ 



A 



