C 780 ] 
may not his affertion be after Mr. de Courtivron’s cal- 
culation, lince they give a difference of time confi- 
derably greater ? 
I am, with the greateft regard, 
Hampton-Court 
in Middlefex. 
June 30, 1754. 
Reverend Sir, 
Your moft humble 
and obedient fervant, 
j 
Clairaut. 
XCIII. A Letter to the Rivht Honourable 
o 
the Lari of Macclesfield, P ref dent of the 
Royal Society, concerning fome new elec- 
trical Experiments , by John Canton, M.A. 
and F. R. S. 
My Lord, 
Read Nov. 14, A s electricity, fince the difcovery of 
1/)4 ' j~X it in the clouds and atmofphere, 
is become an interelting fubjeft to mankind ; your 
lordihip will not be dilpleafed with any new expe- 
periments or obfervations, that lead to a farther ac- 
quaintance with its nature and properties. 
The refinous and vitreous electricity of Mr. Du 
Fay, which arofe from his obferving bodies of the 
one clafs to attract, what thofe of the other would 
repel, when each were excited by attrition 3 received 
no light till the publication of the fecond part of Mr. 
Franklin’s experiments j wherein it appears, that the 
one 
