208 
BRITISH PHARMACEUTICAL CONFERENCE. 
are large growers at the above-named localities, the mass of the flowers are 
grown by cottagers, and collected from them by commissionnaires. In the gly¬ 
cerine plan the flowers could be placed in perfect safety as brought in, and by 
this means all danger from heating by fermentation is thrown out of considera¬ 
tion. I have extracted on the small scale, and by the above means, the aromata 
from Heliotropium grandiflorum , Clieiranthus Cheiri , and others. 
ON COMMERCIAL CARBONATE OE BISMUTH. 
BY MR. C. UMNEY. 
(Read at the Bath Meeting of the British Pharmaceutical Conference , Sept. 18G4.) 
Carbonate of bismuth, occasionally used in medicine, is seldom obtained 
pure, but occurs in commerce mixed with various proportions 0 f basic nitrate 
of bismuth. 
It has been asserted that this nitrate is 'present in large quantity ; it must 
therefore either be put in as an adulterant, or else be formed in the production 
of the subcarbonate. The experiments I have made upon six samples of carbo¬ 
nate of bismuth, obtained from six of the principal manufacturing chemists in 
London, prove the contrary. In one of them it is not to be found at all; and, 
although the nitric acid can be easily detected in the other five (by boiling the 
salt with carbonate of soda, neutralizing with hydrochloric acid, and then ap¬ 
plying the ordinary sulphate of iron test) the quantity is very minute. It can 
scarcely therefore be regarded as an adulterant, but rather as an indication of 
impurity,—doubtless arising from an attempt at economy in the manufacture. 
Carbonate of bismuth is generally obtained by the following process :—Me¬ 
tallic bismuth is dissolved in slightly diluted nitric acid, carbonate of soda is 
then added, which precipitates a subcarbonate of bismuth,—not pure, but con¬ 
taining nitrate of bismuth. The carbonate of soda is preferable to that of 
potash, for if the latter be used, not only is the nitrate formed as well as the 
subcarbonate, but also a portion of carbonate of potash is carried down with 
the precipitate, and is not easily removed by subsequent washing. 
Sometimes a mixture of carbonate of soda and carbonate of ammonia is used, 
but this fails to produce the pure carbonate of bismuth. 
The best process, although more expensive than the preceding ones, is to take 
a solution of the metal in slightly diluted nitric acid, add carbonate of am¬ 
monia, dilute the solution, and boil for ten minutes before the precipitate is 
filtered off. The boiling is necessary, for without it a portion of oxide would 
be retained in solution by the precipitant. 
The composition of the precipitate when so prepared is as described by Lefort 
(Comptes Rendus, 27-268) Bi0 3 ,C0 2 ,H0 ; which gives theoretically in 100 
parts :— 
Teroxide of bismuth....88*30 
Carbonic acid . 8-30 
Water . 3*39 
The following are the results of the analyses for the quantity of teroxide of 
bismuth present in each sample (in 100 parts) :— 
(1) (2) (3) (4) (5) (6) 
89 88*5 86*16 87*66 87*66 86* 
which, I think, are as nearly uniform as can be expected of a commercial article 
no better defined than this carbonate. 
"The carbonic acid present, with one exception, exceeds the normal quantity:— 
(1) (2) (3) (4) (5) (6) 
9*08 8*87 10*95 10*75 8*667 7*28 
