ON ELECTROLYTIC METHODS OF QUANTITATIVE ANALYSIS. 247 
Operating in this way, the results on the preceding page, from | to 11, 
were obtained with 25 c.c. of bismuth nitrate solution=07125 grme. of Bi 
diluted to 150 c.c. 
Experiments 12 and 15 were made with solutions of different strengths 
and larger proportions of nitric acid than those which precede. 
So far as experiments with the simple nitrate solutions were concerned 
the results merely confirmed all our previous experience, as it is very 
difficult to obtain a good adherent deposit on electrolysis except from very 
dilute solutions. 
The results obtained with metaphosphoric acid under the conditions 
specified indicate that the reagent controls deposition in a very marked 
way, and enables us to get good adherent reguline deposits even in 
presence of much free nitric acid and when using a comparatively strong 
current. The use of metaphosphoric acid is therefore attended with 
considerable advantage in the case of simple bismuth nitrate solutions. 
Citric acid has proved quite as etfective as metaphosphoric acid, and 
gives a wider range of utility in general analysis. Moreover bismuth can 
be separated from alkaline citrate solution in good condition and with 
considerable accuracy ; hence we are disposed to prefer the use of citric 
acid to that of metaphosphoric acid in electrolytic determinations of 
bismuth. 
The separation of bismuth from stronger solutions and from other dis- 
solved metals will be considered in the next report. 
The Apparatus employed and the Arrangement of the Circuits for 
Electrolytic Analysis. By Cuarues A. Koun, Ph.D., B.Sc. 
The arrangements for electrolytic work described in this portion of the 
Report have been fitted up in the Chemical Laboratory of University 
College, Liverpool, where the work on the determination of antimony and 
tin and their separation has been carried out. 
A set of five secondary cells charged by a dynamo were employed 
throughout the analyses, 
Electrodes. 
Platinum dishes of about 200 c.c. capacity, and weighing 37-38 
girme., were used as the cathode, and small platinum discs with holes 
bored through them to admit of the escape of the evolved gases as the 
anode. For the determination of both antimony and tin, sand-blasted 
platinum dishes were found preferable to the ordinary polished dishes ; 
this is especially the case when the deposition of a metal is effected 
from a hot solution. The electrodes were kept 20 mm. apart. Glass 
stands with brass supports as described by Classen were used to hold the 
electrodes, the support for the dishes being covered with an asbestos card 
when heating was necessary. 
Voltmeter and Ampere-meter. 
A suitable ampere-meter for electrolytic analysis has long been a de- 
sideratum. The use of the water voltameter which was formerly employed 
has for obvious reasons been abandoned, and the ampere-meters on the 
market are almost all cither too restricted in their range or lacking in 
sensibility ; in addition their internal resistance is so high that it must 
always be allowed for whenever the instrument is not in circuit. The 
