162 



Coated Plates of same kind of glass 



convenience I have distinguished by letters of the alphabet, together with 

 the diameters of the coatings, and their computed charge, supposing the 

 electricity not to spread on the surface of the glass, are set down in the 

 following table*. 



316] The sizes of the coatings were so adjusted that the computed 

 charges of D, E, and F are all very nearly alike. Those of K, L and M 

 were intended to be three times as great as those of the former, and 

 consequently the diameters of their coatings nearly the same. The com- 

 puted charges of A , B and C were intended to be three times as great as 

 those of K, L and M, and consequently the diameter of their coatings 

 about three times as great, and the computed charge of H was intended 

 to be three times as great as that of A. By some mistake, however, the 

 coatings of K, L and M were made rather too small, but the error is very 

 trifling. 



317] My first trials with these plates were to examine whether the 

 charge of the three plates D, E, and F together was sensibly less when 

 they were placed close together than when they were placed at 6 inches 

 distance from each other, that is at as great a distance as my machine 

 would allow of. I could not perceive any difference. This is conformable 

 to the theory, as is shewn in [Art. 185]. I chose to make the experiment 

 with these three plates, as the difference should be more sensible with 

 them than with any of the others. 



318] Secondly. I compared together each of the plates D, E and F. 

 I could not perceive any sensible difference in their charges f. 



Thirdly. The charge of the plate K was found to exceed that of the 

 three plates D, E and F together in the proportion of 1-016 to i. The 

 charge of L was not sensibly different from that of K, and that of M very 

 little different. 



Fourth. The charge of each of the plates A, B and C was to that of 

 the three plates L, K and M together, as 0-905 to i. 



* [Art. 482.] f [See Art. 489, Feb. 4, 1772.] 



