Chemical Affinity in terms of Electromotive Force. 39 
the rate of increase in deficiency was not so rapid, as with 
sulphuric-acid cells. Thus the following four experiments 
may be cited as illustrations of the results obtained in nume- 
rous cases : — 
Hydrochloric Acid : Zinc and Platinum. 
Current-den- Observed 
Current, in ' sity, in micro- differences of ' 
microamperes, amperes, per . potential be- , Value of CR. 
E.M.F. of cell, 
e=E+CR. j 
=C. i square centi- j tween plates j 
metre. =E. 
1 
12-6 1 1-6 
•633 
•633 
234 2-9 
•628 -001 
■629 
55-1 6-9 
•609 -002 
•611 
102-4 12-8 
■5S5 -003 
•588 
224-5 28-1 
•545 -007 
•552 
Calculated E.M.F ="754 
Hydrochloric Acid : Cadmium and Platinum. 
6-5 0-8 
■347 
•347 
11-0 14 
•291 
001 
•292 
14-8 1-85 
•249 
•001 
•250 
33-7 4-2 
•161 
003 
•164 
54-3 , 6-8 
•130 
■005 
•135 
97-8 12-2 
•103 
■010 
•113 
Calculated E.M.F = -.388 
Sulphuric Acid : Zinc and Platinum. 
12-6 
1-6 
•626 
•626 
23-4 
2-9 
•540 
■001 
•541 
55-1 
6-9 
•492 
•002 
■494 
102-4 
12-8 
•439 
•003 
•442 
224-5 
28-1 
•353 
007 
•360 
Calculated E.M.F =-835 
Sulphuric Acid : Cadmium and Platinum. 
6-5 
0-8 
•301 
•301 
110 
1-4 
-259 
•001 
•260 
14-8 
1-85 
•211 
•001 
■212 
33-7 
4-2 
•080 
•003 
■083 
54-3 
6-8 
•033 
•005 
•03S 
97-8 
12-2 
•019 
•010 
029 
f!a.l<»iilat.prl "R 
M.F. - -470 
In each of these experiments the plate-surface was con- 
stantly 8 square centimetres ; the hydrochloric-acid solution 
