270 Mr . Nicholson’s Experiments and 
lated conductors be applied at the touching ends of the fi]k, 
the one will give, and the other receive, eleCtricity until the 
intenfities of their oppofite ftates are as high as the power of 
the apparatus can bring them ; and thefe ftates will be in- 
ftantly reverfed by turning the cylinder in the oppofite 
direction. 
As this difcovery promifes to be of the greateft ufe in elec- 
trical experiments, becaufe it affords the means of producing 
either the plus or minus ftates in one and the fame conductor, 
and of inftantly repeating experiments with either power, and 
without any change of pofition or adjuftment of the apparatus, 
it evidently deferved the moft minute examination. 
1 8 . There was little hope (par. 6.) that cufhions could be 
difpenfed with. They were therefore added ; and it was then 
feen, that the eleCtrified conductors were fupplied by the dif- 
ference between the aCtion of the cuftiion which had the ad- 
vantage of the filk and that which had not; fo that the naked 
face of the cylinder was always in a ftrong eleCtric ftate. 
Methods were ufed for taking off the preffure of the receiving 
eufhion ; but the extremity of the filk, by the conftruCtion, 
not being immediately under that eufhion, gave out large 
flafhes of eleCtricity with the power that was ufed. Neither 
did it appear practicable to prefent a row of points or other 
apparatus to intercept the eleClricity which flew round the 
cylinder ; becaufe fuch an addition would have materially dimi- 
nifhed the intenfity of the conductor, which in the ufual way 
was fuch as to flafh into the air from rounded extremities of 
four inches diameter, and made an inch and half ball become 
luminous and blow like a point. But the greateft inconve- 
nience was, that the two ftates with the backward and forward 
turn were feldom equal ; becaufe the difpofition of the amal- 
gam 
