98 
ings taken every five seconds of the polarisation deflection 
as it diminished to zero. 
(a) and (h) give e in terms of E. 
The cells on which observations were made were 
1. — U tube containing dilute H2SO4, 20 %, with platinum foil 
electrodes. 
2. — Ditto ditto ditto with platinum wire 
electrodes. 
3. — Rectangular battery cell containing concentrated solution 
ZnS04, with Zn plate electrodes of 50 sq. cms. area. 
4. — Rectangular battery cell containing concentrated solution 
CUSO4, with Cu plate electrodes of 50 sq. cms. area. 
Experiments. 
1. Dilute H2SO4 20%. Pt. foil electrodes. 
The curves representing the relation of current to time 
are shown at A for different values of the resistance in cir- 
cuit. They indicate : — 
(a) A very rapid decrease of current during first instants 
after closing circuit. 
(b) After the first 30 seconds the decrease becomes very 
slow, and after some time the readings become constant, i.e., 
the polarisation attains its maximum for the current used. 
The curves representing the variation of the depolarisa- 
tion current are shown at B ; they will be considered more 
fully presently. 
2. Dilute H2SO4, 20%. Pt. wire electrodes. 
In this case the bulk of the decrease from E to E — e is 
over in 15 seconds, and a minimum is quickly reached. 
The same rapid decrease occurs in the “depolarisation” 
curve (e to 0), in which the bulk of the decrease takes place 
in the first 15 seconds. 
The curves are similar to those for 1, but indicate that 
the changes are more rapid. 
3. Concentrated solution of ZnSOi, with Zn plate elec- 
trodes, 
