( 170 ) 
no attraction of the Thread by the Body of the 
Rod ; but when the Thread was held near either of 
the pointed Ends of it, there was a fmall Repul- 
flon of it, and in the Dark a very fmall Light was 
feen at each End of the Rod. 
When the Boy was fufpended upon the Blue 
Lines, he attracted the Thread to him when it was 
held at leaft a Foot diftance from him, and continued 
his attraction to near 75 Seconds, the Iron Rod 
continued its attraction not more than 36 Seconds. 
Experiments made in the Afternoon upon the Boy 
when he was fufpended upon Silk Lines of leveral 
Colours. 
When he was fulpended on the Blue Lines, he 
continued his Attraction jo Minutes, 011 the Scar- 
let Lines 25 Minutes, on the Orange coloured Lines 
21 Minutes. 
By thefe Experiments we fee the Efficacy of 
Electricity upon Bodies fufpended upon Lines of the 
lame Subftance, but of different Colours, and alfo 
that the Attraction continues much longer upon 
Silk than upon Yarn, and confequeutly Silk is the 
propereft Body we can make ufe of to fufpend thofe 
Bodies upon, to which we would communicate an 
Electricity : But of this Subject more when I ffiall 
xeaffume the Experiments concerning the Influence 
of Colours upon Electricity j who am, 
SIR, 
Charter Houfe ,, 
June 12, 1735. Tour's and the Society's moft 
Humble and obedient Servant , 
Stephen. Gray. 
