226 



Journal of Experiments, 1 6 Dec. 1 77 1 



469] Monday, Dec. 16 [1771]. Trials of time in which electricity of stone 

 square, &c. was destroyed. 



The squares were supported on glass, and a piece of tinfoil about i| inch 

 square fastened on each corner. On one of these pieces was fastened a wire 

 from which the pith balls were suspended. The square was then electrified by 

 applying a charged vial, and then a wire communicating with the wall was 

 applied to the other piece of tinfoil. 



With slate the corks closed in 10" 

 Portland 15 



Bremen 8 



gummed glass 5 



The stones had been kept in fore room for several days. The gummed glass 

 had been kept in fore room till the gum began to crack. It was then kept in 

 back room for about 5 hours, and then kept in fore room about ij hour. 



Th. 54. S. H. 22. C. H. + 14. 



Hygrometer corks closed in 4'. The glass being then wiped they closed in 7'. 

 Being then suffered to stand uncovered lor 2 or 3 hours, the corks closed in 5'. 



Th. 54. S. H. 2oJ. C. H. n. 



470] Tuesday, Dec. 17 [1771]. Th. 53. S. H. 20. C. H. + 9. 

 Experiments of [Art. 468] continued. 



Plate vertical. Side sq equiv ^ 

 C 2 sep. a little pos. 10-09 



B - 3^ do. neg. 13-10 3-14 



D 5 do. pos. 9-84 , 



Fore observation. Wire extends very little over. 



J sum 



n-53 



11-71 



n-45 



11-24 



10-51 



10-51 





