( 1x66 ) 
, k. k. Two Pillars with Nutts to fcrew down a piece of 
Board, which has an Iron faften'd to it to receire the up- 
per point of the Spindle, the lower one falling into a Brafs 
Socket, fcrew y to the middle of the Plate of the Air 
Pump, 
1. 1 The Supporters reaching from the upper Board of 
the Ladder to the Pillars, to prevent the Recipients being 
drawn from its place by the motion and tug of the Wheel- 
band, 
ra. m. The fmall Wheel which the Band furrounds from 
the great one, and is i Inch and a half diameter. 
n.n; The Winch which gives motion to the whole. 
The fmall Wheel m. m. making about 15 Revolutions to 
one of the large Wheel D. D. fo that a Body faftned to 
the Spindle g. g. of the fmall Wheel m- m. muft be turn'd 
15 times round to once of the great Wheel 5 and accord- 
ing as it (hall exceed in Diameter the fmall Wheel, fo will 
the Velocity of the Motion of the Extreme parts be pro- 
portionably encreas^d. 
0.0. Are two Screws which faften the Ladder to the 
Floor* 
Experiment L 
Jiff Account of an Experiment made Novemb. 21. 170J. at 
Meeting of the Royal Society at Gre(ham College, Jhewing: 
that Light is Producihik upon a fmft Attrition of Amber on 
Woollen in Vacuo. 
Being prepard with the Machine before defcrib'd, for 
giving a fwift motion to Bodies in Vacuo^ the Amber 
made ufe of in this Experiment was Beads, about the big^ 
nefs of fmall Nutmegs, and Threaded 5 by which means a 
piece of Wood was furrounded with them,, which I bad 
purpofely caus'd to be Turned, with a Groove on the edge 
of it, to keep the Beads, from being difplacd upon a fmart 
Attri*- 
