( ) 
were remov’d to the outfide, and the Finger held within, 
the like motion would be given to them there. General- 
ly the Threads feem to fly the Approach of the Finger 5 
yet fometimes l have feen them jump fuddenly towards if, 
at more than an Inch diftance. 
To conclude this Experiment 3 It is worth taking no- 
tice. That the Figures reprefented by the directed Threads, 
from, and towards the Centre, not only mimick, bur 
feem moft lively to refemble the centripetal, and centri- 
fugal Tendencies of Bodies in their Motions either ways* 
Experiment IV. 
Shewing , That the Effluvia of Glafs , are Capable of 
performing the Office of Attrition 3 Gaufing a Light y 
by falling on an Exhaufled Glafs in Motion , (as if 
ruhhed by the Hand.') 
T HAT the Effluvia of Glafs are very confiderable in 
the Production of divers Phenomena, has already 
been abundantly prov’d 3 but that they fhould aft the 
Part of a Solid Body, by performing the Office of one, is 
{till more admirable 3 And that they do fo, the following 
Experiment fufficiently demonftrates, and feems to coro- 
berate a hint I gave in the 2d Experiment of their Emula- 
ting fucb a Body, by caufing a Thread to fly the approach- 
ing Finger. I took a large Globe Glafs about 9 Inches 
Diameter, which having exhaufled of its Air, I fixe to 
give Motion to it, by the Machine deferib’d in Philof. 
Tran faff, Numb. 304. its Axis handing Perpendicular. 
Another Globe Glafs about the bignefs of the former, was 
plac’d to give Motion 10 it by a new Machine, and 
was wrought with its Axis parallel to the Horizon. This 
laft mention’d Globe, with its Content of common Air, 
was 
