chemical Agencies of 'Electricity. 
49 
X. On some general Illustrations and Applications of the fore- 
going Facts and Principles , and Conclusion. 
The general ideas advanced in the preceding pages are 
evidently directly in contradiction to the opinion advanced by 
Fabroni, and which, in the early stage of the investigation, 
appeared extremely probable, namely, that chemical changes 
are th e, primary causes of the phsenomena of Galvanism. 
Before the experiments of M. Volta on the electricity 
excited by the mere contact of metals were published, I had 
to a certain extent adopted this opinion ; but the new facts 
immediately proved that another power must necessarily be 
concerned ; for it was not possible to refer the electricity 
exhibited by the apposition of metallic surfaces to any che- 
mical alterations, particularly as the effect is more distinct in 
a dry atmosphere, in which even the most oxidable metals do 
not change, than in a moist one, in which many metals un- 
dergo chemical alteration. 
Other facts likewise soon occurred demonstrative of the 
Same thing. In the Voltaic combination of diluted nitrous 
acid, zinc and copper, as is well known, the side of the zinc 
exposed to the acid is positive. But in combinations of zinc, 
water and diluted nitric acid, the surface exposed to the acid 
is negative ; though if the chemical action of the acid on the 
zinc had been the cause of the effect, it ought to be the same 
in both cases. 
In mere cases of chemical change likewise electricity is 
never exhibited. Iron burnt in oxygene gas, properly con- 
nected with a condensing electrometer, gives no charge to it 
during the process. Nitre and charcoal deflagrated in com- 
MDCCCVII. H 
