179 
44-5. It appears, from the investigations of this 
distinguished chemist, that the elements of bodies 
are not only separated from each other by the opera- 
tion of Galvanic action, but are actually transferred 
to distant places, in a state or condition which, for 
a time, entirely suspends the exertion of their che- 
mical powers. Thus, if two portions of a neutral 
salt, as muriate of soda, be exposed,- in separate 
glasses, to the respective poles of the Voltaic battery > 
and the circuit be completed by a moistened sub- 
stance, plunged on each side into an intermediate 
vessel that contains pure distilled water, the salt in 
each glass undergoes decomposition. At the posi- 
tive pole, the acid is attracted, and the alkali is re- 
pelled : at the negative pole, the reverse operations 
take place ; while the repelled alkali from the one 
side, and the repelled acid from the other, meet in 
the middle vessel, and recompose muriate of soda. 
" So from the general phenomena of decomposition, 
and transfer, it is easy," says Mr Davy, " to explain the 
mode in which oxygen and hydrogen are separately 
evolved from water. The oxygen of a portion of 
water is attracted by the positive surface, at the 
same time that the hydrogen is repelled by it ; and 
the opposite process takes places at the negative sur- 
face ; and in the middle, or neutral point of the cir- 
cuit, whether there be a series of decompositions and 
recompositions, or whether the particles from the 
extreme points only be active, there must be a new 
combination of the repelled matter V 
* Phil, Trans. 180". 
