252 REPORT—1896. 
After adding the sodium sulphide to the antimony chloride the solu- 
tion was filtered into a platinum dish, diluted to 175 ¢.c. with water and 
electrolysed. The deposited metal was washed successively with alcohol 
and ether and dried in the air bath at 80° C. before weighing. 
Series I. 
Influence of varying quantities of Sodium Sulphide on the Deposition of 
Antimony. 
The object of this series of experiments was to ascertain how varia- 
tions in the quantity of sodium sulphide present, in excess, in the solution 
of the sulpho-salt, affected the deposition of the antimony, and what 
degree of accuracy was obtainable with varying quantities of metal under 
the most favourable conditions. 
The electrolyses were in all cases conducted in the cold solution and 
allowed to go over night; an excess of sodium sulphide above that 
required to form the sodium sulpho-antimonite was always present. The 
results are recorded in the following table :—- 
Experi- | Antimony Antimony Sodan aut C.D.09 | EMF. | Time: 
| phide solution scent 
ment taken; grme. | fuund: grme. Rdaed Amperes Volts hours 
1 0:1010 071065 inere: O14 | 2:5 193 
2 0:1010 01076 eee O19 1 eel: 193 
3 01010 0 1062 1B, O15 32 193 
4 0°1515 0:1572 225 ©.c. O18 eee 173 
5 00505 | 0:0516 iD: 1.5 O17 bE 174 
| 6 01010 0:1013 30 c.c. 0-19 }> ele 183 
| 7 0:2020 02021 30 5, 015 17 174 
8 0:2020 0 2023 Sines O18 eva 2se 183 
9 0:0505 00508 Seed. ONG. ep ae 17k 
10 0:0202 00202 S0 bre | 0200 St eet 173 
11 0-0101 0:0100 a0 Ge Og [ae 174 
12 0:0505 0:0508 102.5 | 0°20 (E26 18 
13 0:0202 00204 ip: 75 } 0 20 2°7 18 
| 14 00101 | 00098 | LO; 0:20 | 25 18 
Experiments 1-5 show that with only 15 c.c. of sodium sulphide 
solution per 071 grme. of antimony high results are obtained, whereas 
with double the proportion the results are accurate (No.6). But in experi- 
ments 7 and 8, although the quantity of sulphide added is double that in 1 
and 2, the proportion to the antimony present is the same. This apparent 
abnormality is due to the fact that unless a certain excess of sodium sul- 
phide is present a small quantity of sulphur is precipitated with the 
antimony on the cathode, hence the high results 1-6, and the excess of 
sulphide is necessary to keep this sulphur in solution The proportion of 
sulphur thus separated at the cathode appears to be independent of the 
quantity of antimony present, within limits. According to experiment 5, 
30 c.c. of sulphide should be insufficient for 0-2 grme. antimony, but Nos. 7 
and 8 show that this is not the case ; on the other hand, experiment 12 
points to 20 ¢.c. as the right quantity of sulphide per 0-1 grme. of metal. 
In all cases sulphur is separated at the anode. Whenever it comes down 
with the antimony at the anode the deposited metal, which is usually 
bright and metallic in appearance, is always dull and almost black ; this 
was the case in experiments 1-5. 
