Chemical Affinity in terms of Electromotive Force. 21 
Lead Sulphate suspended in Zinc-sulphate Solution. 
= Zine-Cadmium Zinc-Copper 
p | — +Cadmium-Lead. — Copper-Lead. He 
| os | i. | 
: 0-1 587 | 3g9 | = 53 a l= 37 | 536 | 
. “AE "160 = l= 1-114 mule = 
| 5 520 a Bett =) ee ae 504 | =520 | -520 
Par SL =) ators Sa. peer epee | 
| 10 512 se} —512 | _ 603 | =5l | 512 | 
142) Tae a ee ee, 
| 20 501 Hey root has i= 0s fh-802 
ioc 
oO) 491 |, geg | = 491 491 
40 | -487 487 | 
e|  --487 487 | 
5°75 487 487 | 
Lead Sulphate suspended in Cadmium-sulphate Solution. 
mM. Zinc-Lead. ieee recat Mean. 
0-1 50 | Tit —-550 | -550 
05 587 “577 (= 087 | 887 
la} oe . 
10 ot ea a 586 | =529 | -529 
fs 1114) _, as 
2:0 BI aoe 506} =518 | -5185 
30 514 514 
40 509 509 
50 OS 505 
| 575 501 501 
From these mean values for the voltaic constants the 
following numbers are deduced as the thermovoltaic constants 
for electro-lead in contact with solid lead sulphate suspended 
In zinc- or cadmium-sulphate solution ; the heat of displace- 
ment of lead from (solid) lead sulphate by zine forming 
solution of zinc sulphate of strength m ZnSO, 100 H,O being 
106090 —73800 —h=32290—A); 
where 106090= Zn, O, SO3 aq. (m='25), 
73800 = Pb, O, SO aq. (solid), 
h=heat of dilution of m ZnSO, 100 H,O to 
25 ZnSO, 100 H,O (§ 160). 
