1905 - 6 .] Electrolysis through Precipitation Films. 
451 
B. M/ 12 Ammonium sulphate solution. 
(1) No diaphragm, conductivity *00971 mho. 
(2) Filter paper, conductivity . *00967 „ 99*6 per cent. 
(3) Gelatinised paper, con- 
ductivity . . *00954 „ 98*2 „ 
Attempts in the first case to form a serviceable film of aluminium 
hydroxide, in the latter case of chromic hydroxide, completely 
failed. 
2. Aluminium hydroxide film. Ammonium sulphate solution. 
The following is the complete record of the measurements made 
in one experiment, and may be taken as typical of them all. 
A. Ammonium sulphate solution, 0*15 mol. per litre. 
Time in Bridge reading Resistance Conductivity 
Minutes. in mm. Box. in mhos. 
508*5 550 
Electrolyse for five minutes each way with ten-volt direct current* 
replace with fresh solution — 
508*2 550 
Electrolyse three minutes each way — 
508*3 450 *001879 
B. T5m (NH 4 ) 2 S0 4 + *033m A1 2 (S0 4 ) 3 in one limb. 
*15m (NH 4 ) 2 S0 4 + *2m NH 3 in other limb. 
0 
509-5 
550 
3 
511*5 
)> 
6 
511*8 
9 
512*0 
12 
511*7 
5 ) 
15 
511*2 
18 
510*4 
>> 
21 
509*0 
>> 
24 
507*2 
>> 
27 
505*5 
*001908 
