i BW. 3. 
0 hours = . 0 hours SS 9 hours 
aT ? H 
: ; 
| ! 
i : / 
- / 
j / 
| / ‘s , 
v {OO 
16 i 16 i | 
Ae ? 
| | 
\ { 
} 
24 24 } 
{ 
582 32 | 
{ 
| 
ai 
f 
40 40 40 { 
{ 
\ 
, 
u 
48 48 48 ( 
> 
\ 
/ 
56 / -56 56 
} 
i 
' 
- | 
c4 64 64 | 
% 72 12 
i 
as {80 80 
Fig. 1, Double liquid cells; 2, 3, Single liquid cells; Series 1, 2, 6, 8, bichromate 
of potash; 3, 4, 7, 9, bichromate of soda; 5, sulphate of copper, Daniell’s. 
