Mr. Bennet’s Dejcriptton , &c. 27 
peg, which is made round at one end and flat at the other, two 
flips of leat gold are fattened with pafte, gum-water, or varnifh. 
Thefe flips, fufpended by the peg, and that in the tube fatt to 
the center of the cap, hang in the middle of the glafs, about 
three inches long, and a quarter of an inch broad. In one 
fide of the cap there is a fmall tube g , to place wires in. It is 
evident, that without the glafs the leaf gold would be fo agi- 
tated by the leatt motion of the air, that it would be ufelefs ; 
and if the electricity (hould be communicated to the furface 
of the glafs, it would interfere with the repulfion of the leaf 
gold ; therefore two long pieces hh of tin-foil are fattened with 
varnifli on oppofite (ides of the internal furface of the glafs, 
where the leaf gold may be expected to ttrike, and in con- 
nexion with the foot. The upper end of the glafs is covered 
and lined with fealing-wax as low as the outermoft rim, to 
make its infulation more perfect. Tab. III. fig. 1. reprefen ts 
the inttrument joined together, and ready for ufe. 
The following experiments will (hew the fcnfibility of this 
inttrument. See Tab. IV. 
itt, Powdered chalk was put into a pair of bellows, and 
blown upon the cap, which electrified it pofitively when the 
cap was about the dittance of fix inches from the nozzle of the 
bellows ; but the fame ttream of powdered chalk electrified it ne- 
gatively at the dittance of three feet, as reprefented in fig. 2. and 
3. In this experiment there is a change of electricity from 
pofitive to negative, by the difperfion or wider diffufion of the 
powder in the air. It is alfo changed by placing a bunch of 
fine wire, filk, or feathers, in the nozzle of the bellows, and is 
wholly negative when blown from a pair of bellows without 
their iron pipe, fo as to come out in a larger ttream ; this latt 
experiment did not anfwer in dry weather fo well as in wet. 
E 2 The' 
