2 1 2 "Journal of Experiments, 1 77 1 



440] 3RD NIGHT. 



From the two other nights' experiments it seemed as if the positive bottle 

 electrified the plates sensibly stronger than the negative one: why there was 

 not the same difference this night I cannot tell. 



Plates east and west. Wires straight. 



441] Two pair of large corks were made, each of which was found to 

 separate with the same force. The weight of one pair of them was then made 

 four times as great by the addition of lead to them. 



The quantity of electricity in 3rd made vial was then compared by means 

 of these corks with that of a glass plate with circular coating 2-4 inches in 

 diameter and about -06 thick, by touching the glass 8 or 9 times the electricity 

 was reduced from strength requisite to make heavy corks separate to that 

 requisite to make light corks separate, or was reduced to J, therefore the vial 

 should contain 12 times as much electricity as the glass plate and wire by 

 which communication was made, which was about 12 inches long*. 



442] Three coated plates were made 



CDF 



Thickness -06031 -05908 -05914 inches. 



Diameter of coating 1-82 1-79 i'?85 



Therefore square of diameter of \ 



coating by thickness, or com- 1 54-92 54'23 53'88 



puted power of plate J 



Mean 54-34. (D is cased with cement.) 



A circular coating 5-39 inches diameter was made to thick plate in place 

 where its thickness seemed -178, therefore its computed power is equal to the 

 sum of foregoing three plates. The proportion of thickness to diameter is nearly 

 the same. 



Two sliding coated plates were made for trying the foregoing, the trial plates 

 being electrified negatively, the others positively. 



* [See Arts. 413, 582.] 



