274 W. Hallock—Smee Battery and Galwanie Polarization. 
branch of the primary current goes to strengthen the current 
from the polarized voltameter through the galvanometer; in 
the second place a branch of the secondary current (from the 
w, let W_be the resistance in the circuit of the galvanometer 
(150,000 S. E. or 830,000 S. E.); let further 7 be the intensity 
of current in the galvanometer, 7’ that in y and 7?” that in w an 
I, that when E is closed through (7+ W) alone, i. e. I= ees 
}e 
If now we call the force of polarization P, we have according 
to Ohm’s laws 
i=7t'—i"; E=i’'y+iw; P=—?"w+iw, 
whence we obtain by substitution and transformation, 
pasty, w.i—-BE+iW or P=(t-1) eo + W 
If in this last equation we neglect y=100 at the most, as added 
to W=330,000, we have 
a Be | 
P=W, i—“(i-I (1) 
[ x ) 
From (1) we see that only when en Gan We put Pp=W., 
which is very seldom the case, for 7 rarely exceeds 5 or 6 S. E. 
and w varies between 0°38 and 5:0 S. E. ‘I increased the resist 
ance 7 to 100 S. E. in order to make * smaller and more accu 
rately determinable. All the values of polarization given below 
were calculated with formula (1). 
Inasmuch as these experiments on polarization were under- — 
taken with a view to testing whether we can a priori calculate 
the electromotive force of polarization from the thermal equiv 
lent of the chemical reactions which take place thereby, some 
side experiments, more or less directly allied to this questo” 
were made. For example, Exner* wishes to approximate the 
thermal equivalent of the compound PtCl, out of the difference 
in the polarization of HCl between platinum and betwee 
graphite electrodes, 1:26 D, and 1-60 D.; upon ue supposition 
that all the evolved chlorine in the one case dissolved off platt- 
num to PtCl, To prove the incorrectness of this suppositio® 
* F. Exner, Wien. Ber,, xxviii, 1878, und Wied. Ann., vi, p. 353, 1879. 
