G. Bants — Repulsion of Tivo Metallic Disks. 101 



in the maximum case, or about 1/3 of this in the minimum 

 case. The differences are to be referred to the distance apart 

 of the plates, which was not always measured in the earlier 

 experiments. 



9. Plates electrically charged. — The endeavor was next 

 made to overcome the repulsion of plates by aid of opposite 

 electrical charges placed upon them. The experiments at 

 present will necessarily be somewhat crude since the pier is 

 liable to warp during the time in which the observations are 

 made. Nevertheless the corroboration obtained is of great 

 value. 



The observations were made in time series when the plates 

 were close together. For plates further apart, this is not 

 necessary, but in the absence of other than the air damping, the 

 suspended plate oscillates so that mean values have to be 

 taken. 



In fig. 5 I have inscribed the first observations from plates 

 close together. In series 1 to 4, the plates are probably not 

 far enough apart, though the contact position, C, is still beyond 

 the equilibrium position by about *014: cm . It was not necessary 

 to wait for the uncharged position of the plates as this remained 

 pretty constant long before and after the experiments. In 

 series 5, 6, 7, and 8, the distance apart is increased about -04:2 cm , 

 and there is no danger of actual contact (free space -056 cm when 

 charged), so that actual repulsion is in question. 



Table I. — Summary. 



a 



1 



2 



3 



* 



5 



6 



7 



8 



9 



10 



11 



12 



B 6 



d 



AN 



d' 



Fobs. 



V 



comp. 



JFr obs. 



F' R 



comp. 



AN 



Fr /F'u 



X 



y 



/ 





cm 





cm 



volts 



volts 



dynes 



dynes 







cm 



cm 



dynes 



II 



•056 



•039 



•075 



125 



7-43 j 7-1 



2-54 



•110 



2-8 



•036 



+ •020 



4-7 



III 



•044 



•014 



•051 



62 



3-56 2-85 



•94 



•044 



3-0 



•0146 



+ •029 



1-90 



IV 



•102 



•021 



•112 



12-5 



993 215 



1-37 



•033 



1-57 



•003 



+ •096 



•46 



V 



133 



•016 



•141 



12-5 



11-3 ! 1-27 



1-04 



•019 



1-22 



•001 



+ •132 



•19 



I 



•014 



•045 



036 



12-5 



1-90 114- 



2-93 



1-75 



1 39- 



•85 



- -84 



no- 



Table I shows the essential data of these and the other 

 similar experiments in which the distance d in cm. between 

 the plates is gradually increased. AJV is the difference of dis- 

 placement observed, when plates were respectively charged and 

 uncharged. A/V thus shows the displacement of the suspended 

 plate in half centimeters. From AJV the approximate electric 



