relative to Light and the eleftric Fluid. 189 
yet I find that weaker and ftronger {parks differ in apparent 
colour : Some white, blue, da red ; —U white ; 
weak ones, red." 
Several objections here prefent théfofelves: Some of shed 
arifing from the hypothefis itfelf ; and others from the com- 
parifon of light with found. 
Inrefpe& of theformer, if univerfal Space i filled Sik: a fes 
tle elaftic fluid, (fo as to exclude any vacuum) that fluid muft 
always be at reft, and therefore by the hypothefis always invi- 
fible ; and confequently there would always be univeríal dark- 
nefs. Or if any part of the fluid could be put.in motion, the 
whole of-it muĝ be in motion : for. not one particle of it 
could move, without moving, in the-direction of its motion, 
the adjoining one, and this the.next; and fo on, ad infinitum. 
In this cafe, the leaft motion, . Wherever it might commence, 
muft produce univerfal motion ; and. confequently, univerfal 
light : between "which, and univerfal darknefs, there could be - 
no medium. - 
But if the meaning $ the-expreffion be, what it was proba- 
Fe intended: to im that. univerfal fpace, inftead of, bring; filled 
ry E ede which difturbed that fluid, caufe a Eur appear? 
ance ? Would not the inhabitants of the fea and air, in all their 
motions, befpangle both: ; and thereby exhibit the various co- 
lours according to the different degrees of vibration, which 
thofe motions might occafion in the elaftic fluid ?—As to our- 
felyes, would not a. radiance attend us wherever we went È 
What occafion fhould we have of candle-light, when a quick 
vibration of the hand, or of machines made for that purpofe, 
would difpel the night ? Or rather, might we not fuppofe 
there 
