102 C. Barus — Repulsion of Two Metallic Disks. 



force (ignoring the repulsion of plates) may be computed as 

 above, F' n = 65'2AiV. This is given as F' n computed in the 

 seventh column. 



Plates were charged by aid of a storage battery to the 

 potential shown under Fobs, (volts), in column four. From 

 T^and d, the attraction of plates F R may be computed, since 



F' R =:AV'*/87rd* 



A = 7rB 2 being the area of each plate. The results are given 

 in column six, and the F/F' in column 9. 



Fig. 5. 



Fig. 6. 



m £0 40 60 m SO 40 



6 



ao\ 







5 









4 









a 





3 









2 



t 







1 



|,4 



\ 









d- 



\ 



^ 



-05 e7ri 40 C7rb lb cjri 



Furthermore the potential V may also be computed from 

 F R as usual, and this is given in the fifth column. 



From the computed values of F' R since F' R equal to 

 65*2 X AiT', the true value of the displacement in the absence 

 of repulsion, AJV\ may be computed, the result being given in 

 the eighth column in cm. It shows the corresponding dis- 

 placement of the suspended plate in half centimeters. 



The two values of A A" and AA^' now give us the displace- 

 ment due to repulsion in cm., 



x= (AA'— AA)/2 



as shown in column 10. Again, the distance apart in cm. of 

 the uncharged plates d' is given in the third column, being 



