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*• 
A Continuation of the Experiments on the Attrition 
of Clafs. 
Procur’d a Giafs nearly Cylindrical, of the Length 
and Diameter about feven Inches each, whofe motion 
was given by a Machine of a new Contrivance , its Axis 
lying parallel to the Horizon, which in like Experiments 
heretofore made, wasDiametrically oppofite to if. With 
this new Method, after the Cylinder was exhaufted of its 
Contain’d Air, and the Motion made by the Wheel, it fuc- 
ceeded in refpeft to the Light produc’d upon the Attrition 
of it, as in the Experiments formerly mention’d. But 
when all its Air had return'd into it, and the Attrition 
and Motion continu’d as at firft, it was not a little fur- 
prizing to behold fronr the poinc of ones Finger to the 
. Giafs, a vigorous Light, which began ( as has been ob- 
ferv’d ) at the Finger firft ^ and feem’d to Gravitate on 
it, being fencibly to be felt there, notwithftanding the 
Moving Body was not toucht with it by near i an Inch : 
This Light feem’d to iffwe from the Giafs with a confide- 
rable noife, ( not much unlike that of Wheezing, but 
fmarter ) and was eafily diftinguifhable from that made 
by the Operation of the Engine, which was not a fmall 
one- Here obferving the Vigoroufnefs of the Light, and 
the Noife that attended the near touching Finger, when 
the Experiment was made in the Dark, I was willing to 
fatisfie my felf whether it would Exhibit any "Phenomenon 
by Day light $ accordingly, one day in the Afternoon 
between 2 and 3 a Clock, in a very light Room, I found 
that immediately after the Attrition was made on the 
Moving Giafs, and the Finger approacht as before, a 
pure Purple Light became very vifible to extend itfelf 
from the Finger to the Cylinder, and was accompany’d 
with the like premention’d Noife. This Experiment I 
have 
