[ 367 ] 
was remarkable in that way, was owing to the change, 
which the ingredients of the dye produced upon the 
coloured body. I had not then feen what Monf. Du 
Fay wrote upon the fubjed ; but as I have fince, I 
fhall take the liberty to date this matter fairly. 
The late Monf. Du Fay, an ingenious member of 
the Academy of Sciences at Paris, to whom we owe 
fome valuable difcoveries in eledricity, gives an ac- 
count of what is here alluded to, in a memoir, pre- 
fented in the year 1 733. Eledricity was at that time 
in its infancy j Mr. Hawkfbee had, but a little before, 
publifhed an account of his experiments ; which 
brought fuch furprifing appearances of eledricity to 
light, as could not but induce the curious to turn 
their eyes upon that fubjed. In the courfe of thofe 
experiments, he had taken notice of fomething re- 
markable with regard to colours. Mr. Gray fuc- 
ceeded, and having opened a new path, made dill 
further difcoveries in eledricity : he like wife, in giv- 
ing an account of what he had obferved, hinted at 
fomething curious with regard to colours. But nei- 
ther of them appear to have come to any determined 
point in this matter. Monf. Du Fay, who concur- 
red with Mr. Gray, in carrying on eledrical difco- 
veries, with a candour and ingenuity that did honour 
to them both, having entered upon an enquiry (the 
fubjed of the memoir above-mentioned) to determine 
what fort of bodies were mod fufceptible of eledri- 
city, thought proper, in confequence of what had 
fallen from Mr. Hawkfbee and Mr. Gray, to exa- 
mine w'hat effed the different colours had in aug- 
menting or diminifhing the eledricity of different 
fubdances. 
Accordingly 
