P HEP All AT I ON OF L1Q.U Oil B1SMUTHI. 
OH 
the subject has been brought prominently forward in your Journal, it will be 
more satisfactory that it should make its appearance there. 
Take of Subcarbonate of Bismuth, 2 oz. 
Citric Acid, If oz. 
Nitric Acid, 3 oz. 
Water ; 
Solution of Potash; 
Spirit of Wine,—of each what is sufficient. 
Dissolve the bismuth in the nitric acid, add sufficient water to take up the 
nitrate precipitated (from two to three ounces) ; carefully avoiding excess. 
Dissolve the citric acid in the solution thus formed (which will not be perfectly 
clear), and add gradually solution of potash (Liquor Potassse) until the mixture 
is only faintly acid, and gives, after filtration, but a slight cloud on the addition 
of more potash. Filter, collect the precipitate, wash slightly (the presence of a 
trace of nitrate of ammonia in the product is of no consequence), and transfer 
the precipitate to a dish ; add solution of ammonia gradually, until the precipi¬ 
tate is dissolved (a little oxide will remain) ; filter. Measure 4 fluid drachms of 
the solution, add excess of sulphide of ammonium, collect the precipitate on a 
counterpoised filter, wash, dry, and weigh ; 261 grains of the precipitate thus ob¬ 
tained represent 237 of oxide of bismuth. Dilute the whole of the solution with 
water and spirit of wine, in such proportions that a mixture of 1 part of spirit 
with 7 of water shall contain the required number of grains (I generally prefer 
4) to the drachm of solution. In the above process, it is especially necessary to 
avoid the addition of an excess of potash, which appears to decompose the citrate 
formed and precipitate an oxide insoluble in ammonia, and this appears indeed 
to take place to some extent previously to saturation ; a slight waste is therefore 
incurred, by leaving the solution faintly acid, in order to avoid the formation of 
this insoluble precipitate. 
The chief points in which I am indebted to Mr. Bartlett, in addition to those 
mentioned previously, are the following :— 
1. The substitution of carbonate for nitrate of bismuth. The former is far more 
soluble than the latter, which was used by me in consequence of its supposed 
greater constancy of composition. 
2. The solution of the precipitate in pure ammonia. Before the appearance of 
Mr. Bartlett’s communication, a mixture cf citrate of ammonia with free ammo¬ 
nia was used, and heat was applied. 
3. The highly important addition of a quantitative analysis. A margin was 
formerly left to allow for loss (which is not considerable) in the manufacture, 
and, as above stated, the nitrate of bismuth was used as a more uniform salt 
than the carbonate. 
The weak points in Mr. Bartlett’s process appear to be the following :— 
1. The great acidity of the solution from which the citrate of bismuth is ulti¬ 
mately separated, causes the precipitation to be extremely imperfect; there is con¬ 
sequently great waste of material and labour. 
2. The extreme dilution of each portion of the acid bismuth solution, in the 
act of addition to the solution of citrate of potash, seems to determine the preci¬ 
pitation of basic nitrate, insoluble in ammonia, before the double decomposition 
necessary to the formation of the citrate can take place. 
I am, Sir, your obedient servant, 
Thomas P. BlujStt, F.C.S. 
Shrewsbury , April Mh, 1865. 
