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EXPERIMENT XIII. 
Shewing Mr. nairne the above-mentioned 
•experiments ; when the amber had been well- 
heated, and being prefented to a fn (pended thread, 
having fhewn no fign at all of electricity j 
I held it, between my thumb and fore- finger, 
very near the table, but not fo as to touch it, that 
vve might entirely avoid friction. He then blew 
againft it thirty blafts, with a pair of kitchen- 
bellows ; when prefenting it to the thread, it at- 
tracted it, at the diftance of one-eighth of an inch. 
He then blew againft it, thirty blafts more, as 
above defcribed ; when applying it again to the 
thread, we favv it attracted, at half an inch di- 
ftance ; and, on drawing back the amber, it drew 
the thread after it, fix, or eight inches. We re- 
peated the experiment three times, with the like 
luccefs ; and are fatisfied, that the amber was 
made eleCtrical by the fridiion of the particles of 
air againft its fur face ; and not in the leaf by heat - 
ing only. We afterwards excited the amber, 
when it muft have been perfectly cold, but dry, 
by only blowing againft it as before. 
The fame procefs fucceeds with glafs. 
SECTION SIXTH. 
Experiments and Obfervations on the Electricity of fogs, &c. 
in purfuance of thofe made by thomas ronayne, Efq; 
1771, Nov. 14. Half paft eight, A. M. I find 
a fog, not very thick, pretty ftrongly eledrified. 
The balls feparate full half an inch. They keep 
ftationary, there being little or no wind. 
Nov. 19. 
