Difference of charges on parallel disks 273 



If the four jars were charged to 2 + 3 and its electricity communicated to 

 globe 3, it was diminished to 2 4- 2. 



The plate air 4 was charged by jar charged till straw electrometer stood at 

 2 + o, and if jar 4 was charged to the same degree and its electricity communi- 

 cated to jar 2, the corks separated the same if bottom was not touched. 



With plate air i the charge was obliged to be reduced by communicating 

 jar 2 to jar 4 to make the same separation when bottom was not touched as 

 when it was. 



Tu. Mar. 30 [1773]. Th. 56. N. 8. 



The same experiment was repeated, only putting a piece of sealing wax with 

 marks on it supported by glass about 2 inches below the corks to serve by way 

 of comparison. 



Compound plate 

 of [Art. 552] 

 Plate air i 

 Plate air 4 



2+1 

 2+i 

 2+1 



Jar i commun. 

 to 2 + 4 

 jar i to 2 

 i to 2 



2 4. TJ 

 * ~ A 2 



2+1 

 2 



The second column is the distance to which the straw electrometer separated 

 in charging jar with [which] the plate was electrified when the bottom was 

 touched in order that the cork balls should separate equal to marks on wax. 

 The third column is the ratio in which the electricity of the jar was diminished 

 when the bottom was not touched, and the fourth column shews the degree in 

 which the jar was electrified (as expressed by distance to which the electro- 

 meter separated) in order that ..he balls should separate to the required distance. 



N.B. The paper of divisions used for the electrometer was different from 

 that used before, but the divisions nearly of same strength. The marks on 

 sealing wax used for compound plate were nearer than those for plate air. 



The jars i, 3 & 4 being charged till straws separated to 3 + o and the elec- 

 tricity communicated to jar 2, they separated to 2 + i, and the electricity of 

 jar 2 being destroyed and the electricity of the others again communicated to 

 it, they separated to i + 3*. 



Therefore diminishing the electricity in ratio of 95 to 126 diminishes distance 

 to which the balls separate in ratio of 126 to 165, or diminishing the electricity 

 in ratio 1-33 to i diminishes distance in ratio 1-31 to i. 



Result. 



On Monday the excess of redundant fluid on the positive side above de- 

 ficient fluid on negative side in 



ii inch plate with 8 inch coating \ 



3 J 



Plate air i L is 



Plate air 4 



1-88 

 i 



/ 2-14 



* The smaller divisions are equal to ^ of large ones. 

 C.P.I. 1 8 



