C 70s ] 
3. At the Beginning of lad Summer I caufed a 
Machine to be made for ele&rical Purpofes 5 the 
Wheel whereof was four Feet in Diameter. In the 
Periphery of this Wheel were cut four Grooves, 
correfponding with four Globes of ten Inches Dia- 
meter, which were difpofed vertically at about three 
Inches Diftance from each other. One, two, or the 
whole Number of thefe Globes might be ufed at 
Pleafure. They were mounted upon Spindles of 
two Inches Diameter, and their mean Motion round 
their Axis was about eleven hundred times in a 
Minute. As it is next to impoffible to have thefe 
Globes blown and mounted perfe&ly true, I order’d 
the Leather Cufhions, with which they were rubb’d, 
to be fluffed with an elaftic Subftance (curled Hair) 
that the Globes in their Rotations might be as equally 
rubb’d as poffible. You might likewife caufe the 
Globes to be rubb’d by the Hands of your Afllftantsj- 
but under a certain Treatment (of which hereafter) 
the Cufhions excite equally ftrong. The Leather Cu- 
fhions were now-and-thenrubb’d over with Whiting. 
As a minute Detail of the Parts of this Machine 
would take up too much of your Time, I have 
herewith laid before you a Draught thereof. 
4. I lined one of thefe Globes to a confiderable 
Thicknefs, with a Mixture of Wax and Relin, ia 
order to obferve whether or no the Ele&ricity 
would be the fooner or more ftrongly excited 5 but 
I found no Difference in the Power of this Globe 
from the others, which were without this Treat- 
ment. 
5. The Power of Ele&icity is increafed by the 
Number and Size of the Globes to a certain Degree 5 
Y y y y 2 but 
