94 ON THE HEAT EVOLVED DURING 
the several experiments been continued just long 
enough to effect the evolution of a grain of hy- 
drogen. Now I had ascertained, by the very 
careful experiments given in the first three num- 
bers of the table, that the intensity of a Daniell’s 
cell, such as I used, is equivalent to 6°°129 of 
heat, per degree of current; and hence I have 
obtained by simple proportion the numbers of 
column 10, representing, in terms of the intensity 
of Daniell’s cell, the resistances to electrolysis 
due to the quantities of heat in column 9. By 
subtracting these from the numbers of column 5, 
we obtain those of column 11, which, as we shall 
presently see, represent the intensity requisite to 
separate water into its elements and to evolve 
the constituent gases. Columns 12 and 13, con- 
taining new resistances to conduction,* and the 
heat due to them, are calculated from column 11. 
It will be observed that the resistances to 
electrolysis (contained in column 5,) differ ac- 
cording to the nature of the electrodes. With 
platinized surfaces the resistance is considerably 
* T call these, “resistances to conduction,” merely from 
the want of a more appropriate term to distinguish what is 
really a mixture of two distinct sources of resistance. Column 
6 gives the true resistance to conduction. 
