[ 9oo ] 
ftople of glafs. Then the pointed end of the ivory 
conductor was brought oppofite to the middle of the 
bottle, and about two inches from it. Upon doing 
this, the balls were electrified minus •, and more 
fo, as the ivory was moved nearer the bottle in an 
horizontal direction. 
But, on removing the ivory to a greater diftance, 
the minus electricity decreafed j and, at a certain di- 
ftance, there was not any fign thereof remaining : 
and when the diltance was increafed to about eighteen 
inches from the bottle, a plus electricity appeared, 
which continued, even after the ivory was removed 
intirely away. 
After uneleCtrifying the bottle, it was fet again, 
upon the ftand of wood ; and upon another of the 
fame kind, was laid a large iron poker, fo that the 
pointed end was about two inches from the outfide 
coating, and much nearer the bottom than the top 
of the bottle. I chofe the lower part thereof, for 
no other reafon, than to have the poker out of the 
reach of any effeCt that might happen from the co nr 
du&ing-wire, which communicated with the ma- 
chine, and the infide coating of the bottle. The 
other end of the poker, being a large round knob, 
was about one inch from a rod of iron, which com* 
municated with the earth. Under thefe circumt- 
ftances, when the infide of the bottle was electrified 
phis, the outer coating became minus , as ufiial. 
It is to be obferved here, that the p/us appearance 
in the poker was caufed by that portion, of the fluid, 
which was driven off from the outfide of the bottle, 
by the repulfive force of the fluid conveyed into the 
bottle. And this confirms the reafoning upon the rer 
markable 
