236 "Journal of Experiments, Feb. 4, 1772 



Coated Balls closed Separated 



plates in seconds again in 



K of Nairne } 

 in cement / 



L 10 did not separate again in several minutes 



Double 1 A 15 i'. 15" 



plates J B 10 i'. 30" 



closed almost instantly, separated again in about 10". 



488] Three sliding coated plates were made, each covered all over with 

 tinfoil on one side, with a slip of tinfoil 1-8 by -9 in. on the other. Two flat 

 pieces of brass were also prepared, one 1-8 by -9 and the other 1-8 square. 



The tinfoil was divided in breadth into 6 equal parts, and the breadth of 

 the coated surface is expressed in those divisions or in 6 th parts of the breadth*. 



The first plate was one of exper. rosin -345 thick. 



The 2 nd , 2 plates of glass with rosin between. 



The 3 rd , a bit of the large piece of whitish plate glass. . 



The rosin sliding plate when the breadth of coating = 24) 



^ contains as much 



2 nd = I2J 



electricity as the double plate A. 



The 3 rd sliding plate when its breadth => io contains as much electricity 

 as plate F of Naime. 



Therefore i division on 



2 nd sliding plate contains -Jf I of the electricity 



3 rd 

 in plate D, E, F, or G of Nairne. 



7 inches of additional wire answers to r inch of computed power in plates 

 of Nairne. 



2 trial plates were made for the plates I, K, L and M of Nairne out of 2 of 

 the ground plates first got from Nairne. The dimensions of the coating of the 

 small one was about 3-3 by 3-1, and that of the large one 3-7 by 3-4, the 

 thickness of glass unknown. 



Two trial plates were also made for the plates A, B and C of Nairne out of 

 the old ground plates E and F. F, the smallest, was 5-7 square, and E was 

 6-3 by 6 nearly. 



Two trial plates were made of crown glass for the plate H of Nairne, the 

 small one 5-7 by 5-1, the other 6 by 5-9. 



489] Tuesday, Feb. 4 [1772]. Th. 47. S. H. 17. C. H. - 5. 



Trial of plates D, E, F and G of Nairne, and of the 2 double plates, the 

 plates E, F and G being cased with cement : tried by means of additional wire f. 



* [See Art. 297.] f [Art. 318.] 



