1042 Dr. ingenhousz’s Experiments 
force to flop its motion as it required to be brought from 
a ftate of reft to that of motion. 
Let us now confider attentively the ftate of a body 
fituated, as I have before defcribed, in the fphere of ac- 
tion of an excited eledtric ; as, for inftance, a cake of re- 
fin, a flat glafs, or any other non-condudting fubftance; 
or, in other words, let us confider the ftate of the metal 
plate placed upon the refinous cake of an eledtrophore, 
fuppofing this cake to be excited with a pofitive eledtri- 
city; which eledtricity it acquires eafily by Aiding the 
knob of a Leyden phial, charged in the common way, 
over its furface and by various other ways. The fuper- 
abundant eledtric fluid of the cake repels the eledtric 
fluid of the metal plate to its farthermoft extremity, and 
excites there an accumulation of that fluid ; or, in other 
words, produces there a pofitive eledtricity, whilft it pro- 
duces a negative eledtricity at the furface in contadt with 
the cake. 
If in this condition a condudting body be brought in 
contadt with the metal plate, or within its ftriking dif- 
tance, it receives a fpark from it; which fpark is the ele- 
tric fluid of the metal plate crouded upon the extremity 
of the metal by the repulfive force of the fuper-abundant 
eledtric fluid of the cake. 
If 
