( 613 } 
The E.M.F. of the Cuark-cell at t° may, according to KAnLe, 
be represented by: 
E, = Ey, — 0,00119 (t—15) — 0,000007 (t—15)? . . (2) 
CALLENDAR and BARNES give as the result of their measurements: 
E, = E,; — 0,001200 (t—15) — 0.0000062 ({—15)? . . (3) 
From (2) follows : 
dE 
y= 000119 —0,0000140(t—15) . . . « (2) 
a 
From (3): 
dit 
—, = — 9,00120 — 0,0000124(t—15). . . . . (8a) 
According to JAEGER and KaAHLe, the E.MF. of the CLARK-cell 
at 15°,0 C. is 1,4328 volt. 
If we now calculate the temperature-coefficient at 18°C. (7=291) 
we find : 
According to (2a) 
dE 
is = — 0,001232 Volt 
T = 291 
According to (3a) 
E 
a = — 0,001237 Volt. 
dt 
SaR 
For the E.M.F. of the CrLARK-cell at 18°C. (7 = 291) we find: 
Eg9) — 1.4291 Volt. 
If these values are introduced into equation (1) p. 611 and 
everything expressed in caloric measure, 1 volt-coulomb being taken, 
in accordance with the measurements of Jann’) as being equal 
to 0,2362 cal. we obtain: 
E.= 2 X 40745 = $4490 calories. 
-). Wiep, Ann. 25. S, 49 (1885), Zeitschr, fiir phys. Chemie 26.585 (1898), 
