Specific Velocities of Ions in the Discharge from Points. 91 



sures in columns according to the descending order of V; 

 divide each column into two at its centre ; take the means of 

 the pressures in the upper and lower halves of each column 

 respectively; and plot the two pairs of corresponding pressures 

 thus obtained, In case a these points will fall on AA, say at LL; 

 in case b they will fall on BB at MM ; and in the latter case, 



Fig. 4. 



-Hydrogen. rc=19. 

 Negative. 



B. II. 











•/ 













/ 













/' 





A 









i 





N ^ 



\ 





// 

 // 















































// 

 // 







\ 





/ 

 / 













y 













( 

















/ B 





A 





/ 







\ 



\ 



/ 











k 









/ 



■ % 



\ 







/ 





\ 



* 



i 



v 









Pi 4 



A 





/ B 







\ 



/ 







/ 



\ 







/ 

 B 



A 





« P'Z 



2 t> 2 



Positive. 



A 



\ 



r 







^ 



c 







/ 



5»\ 



A 







B 7 







Microamps. . . 32 



V-2 



Px 11 



A v 





/ 8 







Nj 



»\ 







b/ 



A 













1-6 





A, 



1/ 



B 







h 







B 



1 



A 











as there cannot fail to be errors of purely accidental character 

 also present, we should expect the points to show a trace of 

 the " a " effect by falling somewhat off BB as at NN. 



In fig. 4 are given the results of the application of this test 



