310 © On the Theories of the 
“It explains the decomposition of those 
bodies only, which contain hydrogen as one 
of their elements. And though it has been 
ably contended by Mr. Sylvester, that the 
presence of water is, in every case, essential 
to Galvanic decompositions, yet the fact does 
not appear to be sufficiently established. Even 
if it were ‘verified, the agency of moisture 
might be supposed to consist in its giving that 
peculiar interrupted transmission, on. which the 
efficacy of Galvanic electricity in disuniting 
the elements of bodies seems much to depend. 
2. If the postulate of Dr. Bostock be 
. granted, that electricity is evolved by oxida- 
tion, we shall be entitled to assume the reverse 
as equally true, viz. that electricity is absorb- 
ed when oxygen passes to the state of gas. 
In cases, where the positive wire is of an 
oxidable metal, the phenomena accord suffi- 
ciently with the theory ; for by its oxidation, 
electricity may be supposed to be liberated, 
and to form the: required combination with 
hydrogen. But when the positive wire is of a 
non-oxidable metal, oxygen gas is disen- 
gaged ; and in the production of this gas the 
electric fluid might be expected to act, instead 
of being employed in carrying mpretaen te 
the negative wire. 
The same class of phenomena has been 
