C 1414 ) 
Light became more confiderable $ and, I think, the great- 
eft as yet that has been produc’d in any Experiment made 
on this Subjeft 3 and doubt not, but would have been 
more fc, had the inward Glafs fitted nearly to touch the 
inward Surface of the outward one 5 the Effluvia of which, 
(as it feems to me) would then be capable to aft with 
more Vigour on the Exhaufted moving Receiver. But to 
return : I caus’d both the great Wheels to give Motion 
to the Glaffes one and the fame way, with as equal a 
Velocity as they could y yet I did not difeover but the 
Light was then as ftrong, and continuing, as when their 
Motions were made Reverfe : So that f do not perceive 
that a Difenting Motion from each other dees any way 
contribute to the Ebancmnon $ but Motion it felf, with- 
out being preferib’d by Rules, (as this Experiment feems 
to infmuate) is found abfolutely neceffary, as indeed the 
whole Courfe of Experiments on this Head abundantly 
confirm.., I farther obferve, that notwithfta tiding the 
Effluvia feem’d to be equally diftributed on the outward 
Surface of the inward moving Glafs, yet the Light was 
moft vigoroufiy apparent on that fide of it neareft the 
Attrition g And when the Motion of the outward Glafs 
was ceas’d- or the inward one, and the other in Motion,., 
(for upon trial 1 found very little Difference either, way,) 
the Light would continue to appear a confiderable time 
within the Exhaufted Glafs, till the Effluvia or the other, 
were no longer capable to aft with fo much ftreogtfa, as 
to lay hold or affeft the inward one. I likewife obftrv’ci, 
that after both Glaffes had been in motion for forme: ume, 
and the Hand apply’d all the while on the outward cue, 
that then the Motions ceafing, and no Light appearing c 
was but approaching my Hand near, the Surface ox ; n 
outward Glafs -to produce F.lafhes- of Light like Ligutm g 
in the inward one, the Effluvia feemfug- then fo be w 
vigoroufiy puftu upon it by the approaching Hand* h 
