254, REPORT— 1896. 
is reliable, as shown in Nos, 2 to 6, though rather less so for small quan- 
tities of metal than when the electrolysis is conducted in the cold solution. 
The temperature should not exceed 50° to 60°. The deposit is bright 
and metallic in appearance, and adheres well to the dish. 
Series ITT. 
Deposition of Antimony from Ammonium Tartrate Solution. 
Parodi and Mascazzini (loc. cit.) state that antimony can be deposited 
from a solution of its chloride in ammonium tartrate, but give no experi- 
mental data. According to Classen an adherent deposit is obtained from 
a potassium tartrate solution, but the separation takes too long to be of 
value for analysis. As very few results have been published on this 
method a series of experiments were tried. These show that the complete 
deposition of antimony from a solution of an alkali tartrate is possible, in 
about nineteen hours, with a current density per 100 sq. em. of 0°15 am- 
pere. The deposit, however, does not possess the bright metallic appear- 
ance of that obtained from sodium sulphide solution ; it is dark and dull 
and does not adhere very fast to the dish. Still it can usually be washed 
without loss, although with quantities of metal, above 0-1 grme., this 
was not possible, hence the low result in No. 1. Also when the current 
is allowed to exceed 0:15 ampere per 100 sq. cm. the deposit is less 
adherent and apt to wash off. Nos. 2, 9, and 10 illustrate this. The method 
of analysis was to neutralise the solution of antimony chloride and add 
the ammonium tartrate in a 12 per cent. solution, the electrolysis being 
conducted in the cold solution and over night. The following results were 
obtained : 
. Antimony Antimony Bt ; 
Experi- | ~ fakes fouud< Tartrate C.D.400 E.M.F. | Time: 
ment Gane’ Grine. rey Ampeies Volts hours 
1 0°2036 0:2020 3 015 3°6 183 
2 0:2036 0:2003 3 0:18 36 183 
3 0-1018 0:1018 25 0-14 37 19 
4 01018 01019 4 013 37 193 
5 071141 0:1140 6 014 33 ify) 
6 0:1141 01142 6 0-15 34 19 
7 01018 0°1025 3 013 33 182 
8 0:0509 0-0504 3 O15 3-4 183 
| 9 0:1018 0:0983 3 0:18 35 184 
10 0:0509 0:0477 3 0-18 37 | 183 
Variations in the quantity of ammonium tartrate added above 2°5 grme. 
have no influence on the accuracy of the method, as is seen from Nos. 
3, 4, and 5. 
Summary. 
The most reliable method for the electrolytic estimation of antimony is 
the use of the sulpho-salt in presence of a large excess of sodium sulphide, 
under the conditions already described. This solution can be electrolysed 
either hot or cold; the latter is always preferable when only small quanti- 
ties of antimony are to be deposited. The saving of time by using the 
warm solution is no great advantage, as the deposition from the cold 
solution requires no watching and can be allowed to go on evernight. 
