294 On the Theories of the 
to apply them to each other, for an instant, 
by their flat faces, and afterward, separating 
them dexterously, to bring them into contact 
with the electrometer. The instrument indi- 
cates, by the divergence of ifs gold leaves, 
what kind of electricity each of the plates has 
acquired ; which proves to be positive in the 
zinc plate, and negative in the copper one. 
To explain the phenomena, in the experi- 
ment which has been just described, it has 
been supposed by Volta, that, during the 
contact of the plates, a movement of the elec- 
tric fluid takes place from one plate to the 
other; and that the zinc acquires just as much 
as the copper has lost. The metals, therefore, 
he denominates motors of electricity, and the 
process itself electromotion, the latter of which 
terms has been adopted by Mr. Davy. From 
subsequent experiments, Volta ascertained 
that the metals stand to each other, in this- 
respect, in the -following order; it being 
understood that the first gives up electricity 
to the second; the second to the third; the 
third to the fourth; and so on: 
Silver,. 
Copper, 
Tron, 
Tin, 
Lead, 
Zinc. 
