THE ELECTROLYSIS OF WATER. 103 
obtained by experiments, the general accuracy of 
which I have myself ascertained. 
Before I conclude, I wish to make a few general 
observations in connexion with the subject of this 
paper. 
Ist. In an electrolytic cell, there are three 
distinct obstacles to the voltaic current. The 
first is resistance to conduction :—the 2nd is re 
sistance to electrolysis without chemical change, 
arising simply from the presence of chemical re- 
pulsion ;—and the 3rd is resistance to electrolysis 
accompanied by chemical changes. 
2nd. By the Ist. of these (the resistance to 
conduction) heat is evolved exactly as it is by a 
wire, according to the resistance and the square 
of the current; and it is thus that a part of the 
heat belonging to the chemical actions of the bat- 
tery is evolved. By the 2nd., a reaction on the 
intensity of the battery occurs, and wherever it 
exists, heat is evolved exactly equivalent to the 
loss of heating power in the battery arising from 
its diminished intensity. But the 3rd. resistance 
differs from the 2nd., inasmuch as the heat due 
P 
