214 'Journal of Experiments ; 1771 



Pasteboard circle 19-4 inches diameter hung on silk strings. 



[Equivalent] 

 Circle plate 19 x 14 did not separate 16-3 



15 did rather doubtful 16-9 



16 did very little 17-4 



17 did more 18- 

 Circle plate 14 x 12-7 did 13-2 



13-4 did rather doubtful 13-7 

 14-4 did not 14-2* 



With circle 1-8 inches diameter on glass -18 thick it separated a little nega- 

 tively with plate 19 x 19, and would most likely not separate at 19 x 21 or 

 19 x 22 = 20 or 2o. Therefore quantity of electricity therein most likely is 

 to that of globe as 20-2 to 12-4 or as 10 : 6. 



446] Thickness of double plate of glass at centre of circle = -285. Diameter 

 of coating = 1-75. 



Being tried against small plate not drawn out, separated considerably 

 positive, therefore quantity of electricity therein might perhaps be to that in 

 globe as ii to 18, and therefore its actual power would be to that of thick 

 plate as 6-6 to 18. The computed power is to that of thick plate as 10-8 to 18. 



A coating 1-45 inches diameter was made on thick plate where the thickness 

 is supposed = -168, therefore computed power = 12-5. This being tried against 

 sliding plates was as follows: 



Small Large 



sliding sliding 



plate 



3 

 4 



5 



therefore quantity of electricity therein seems to be to that of globe as 13-7 

 to 12-6, or 17-4 to 16-3, id est as 14 to 13, 

 therefore actual power = n-6 



diam. plate 

 In thick plate 1-8 diam.. ^.^ = 



do. 1-45 8-1 



double plate 6-14 



TRIALS OF WIRES. 



447] The wires placed horizontally and parallel to each other, one end 

 supported by silk, the other by waxed glass. 



The trial wire consisted of iron wires -14 thick sliding on each other, sup- 

 ported in [the] same manner. 



* [The charges of the globe and the circle of 19-4 inches appear from these 

 numbers to be as 28-9 : 30-7. The diameter of the tin circle, 18-5, was probably 

 calculated from these experiments so that its charge might be equal to that of the 

 globe. The correct diameter would have been 19 inches.] 



