[ 38 ° ] 
was then futficient for the approach of the duft to the 
conductor, in order to fee the particles rife in a verti- 
cal direction, like the filings of iron on the applica- 
tion of a magnet. 
Obf. f. 
On the 27th of June, at 1 afternoon, I perceived 
fome ftormy clouds rifing above the horizon, and im- 
mediately went up to my apparatus j and having ap- 
plied the duft to the key, it was attra&ed with a 
force, which increafed in proportion as the clouds 
reached the zenith. When they had come nearly 
over the wire, the duft was fo impetuoufly repell’d, 
as to be intirely fcatter’d from the paper. I drew 
confiderable fparks from it, altho’ there was neither 
thunder nor lightning. Thefe fparks were of a very 
lively red colour, when I attracted them with my 
finger : they were white and fmaller, when I ufed a 
wire hafted in a glafs tube : they were bluifh, and 
much extended, when attra&ed by fpirit of wine in 
a iilver lpoon. 
Obf 6. 
I applied a piece of refin to the conductor, but 
could draw no fparks from it : however, all, who 
were prefent, heard a noife like that of hairs when 
burnt. It was the fame with fealing-wax, woolen- 
cloth,- linen, &c. Then I took a quickfilver’d glafs, 
and applied to the clean fide a piece of wire of fix 
inches long, whilft the other end was put to the con- 
ductor ; by which I drew a multitude of lmall whitifh 
fparks, which foon cealed, but were fucceeded by a 
noife 
