416 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [November 19 , 1370 . 
In recent experiments with turmeric, I have discovered 
a basic substance, which, separated by ammonia from its 
combinations with sulphuric and nitric acids, presents 
a finely granular semicrystalline precipitate, readily so¬ 
luble in hydrochloric acid. This combination crystal¬ 
lizes in long prismatic crystals with oblique termina¬ 
tions. It is colourless, and much disposed to become 
opaque. 
The nitrate crystallizes in very short prisms with a 
tendency to unite in pairs which, much magnified (f ob¬ 
ject-glass), resembled the disposition of the two lobes of 
some anthers in the Gramincse. 
The sulphate also presents groups of long crystals, 
grouped in a stellate manner, opaque by prolonged dry¬ 
ing in warm air. This salt is also colourless. 
There were indications of another base, resembling in 
some points that existing in calumba root. I say that , 
but believing that there are at least two, mean the prin¬ 
cipal one. 
The colouring matter is quite another product. 
I have some intention of undertaking for another year, 
if health and leisure allow it, the examination of the 
salts of lithia, which I find noted in the desiderata. 
Let me conclude by wishing success to the Conference, 
an organization which may prove very serviceable by 
carefully and earnestly encouraging working bees, and 
by putting in their way what is worth having in forth¬ 
coming Year-Books. 
The Chemical Constitution of Sulphurated 
Potash. 
BY JOHN WATTS, D.SC. LOND. 
The following paper contains an account of some ex¬ 
periments upon which I have been engaged during the 
last few months, in order to ascertain more directly the 
exact chemical composition of sulphurated potash. 
Different chemical works give different and, apparently 
at first sight, discrepant results respecting the reaction 
which ensues when a mixture of potassic carbonate and 
sulphur is submitted to fusion. By some, especially by 
those of high authority, it is asserted that the reaction 1 
takes place according to the following equation, 
4 K, C 0 3 + 5 = Iv 2 S 0 4 + 3 K 2 S 3 + 4 C 0*, 
Sulphate. Sulphide. 
potassic sulphide and potassic sulphate being produced, 
while carbonic anhydride is evolved. By others it is 
stated that potassic hyposulphite is one of the products 
of the reaction, and that either potassic sulphate is not 
produced at all, or the equation proceeds in two stages, 
thus, 
3 K 2 C 0 3 + 4 So = K 2 So 0 3 -f 2 Eo S 3 + 3 C (A. 
Hyposulphite. 
4 K. 2 S 2 0 3 = 3 K 2 S 0 4 + K 2 S 5 . 
Hyposulphite. Sulphate. Sulphide. 
the hyposulphite being resolved into sulphate and sul¬ 
phide when the temperature at which the fusion is con¬ 
ducted approaches ignition. 
A few qualitative analyses of some samples of “sul¬ 
phurated potash, prepared with varying molecular 
proportions of materials, immediately decided in favour 
of the latter equations; the presence of potassic hypo¬ 
sulphite in. considerable proportion was readily esta¬ 
blished, while potassic sulphate was detected only in 
very small quantity, and in one sample disappeared alto¬ 
gether. It is well, perhaps, to mention that there is 
much difficulty in preparing a sample entirely free from 
sulphate, since if the heat employed be somewhat too 
high or too long continued, a proportion of sulphate is 
immediately formed at the expense of the hyposulphite 
present. 
Being now enabled to calculate the percentage com¬ 
position, I proceeded to the quantitative analysis of 
several commercial samples, to see how closely their per¬ 
centage might agree with that which had been deduced 
from theoretical considerations. The samples were pro¬ 
cured from some of the best wholesale houses, and fairly 
represent the article as met with in commerce. The 
analysis resolves itself into the quantitative separa¬ 
tion of a mixture of potassic sulphide, hyposulphite and 
sulphate, but the probable presence of potassic sulphite 
and potassic carbonate must not be ignored, since the 
former may be derived from incipient oxidation, and the 
latter may result from imperfect decomposition. 
There are two methods of effecting the separation of 
sulphides from hyposulphites and the higher oxacids of 
sulphur :—1. By adding to a solution of the salt in ques¬ 
tion a strongly ammoniacal solution of argentic nitrate, 
the sulphur existing as potassic sulphide is alone pre¬ 
cipitated as argentic sulphide, while the remaining silver 
salts are retained in solution by the excess of ammonia 
present; the argentic sulphide is collected and washed, 
and the sulphur estimated either by oxidation or by re¬ 
duction in a current of hydrogen. To another portion 
of the salt, solution of argentic nitrate is again added, 
omitting the previous admixture with ammonia,—argentic 
sulphide is precipitated as before, while at the same time 
the hyposulphite is resolved into a mixture of argentic 
sulphide and argentic sulphate ; when the decomposition 
is complete, excess of ammonia is added and the sulphide 
collected and estimated as before. The amount of sul¬ 
phur corresponding to one-half of the hyposulphite 
present is then calculated, by deducting, from the total 
amount of sulphur found, the weight of sulphur as 
obtained in the first operation. 
2. By Werther's method. Recently precipitated cad- 
mic carbonate is added in excess to the solution to be 
analysed; double decomposition ensues, potassic car¬ 
bonate formed, and cadmic sulphide precipitated; this 
latter is washed, oxidized with fuming nitric acid, and 
the sulphuric acid estimated as baric sulphate. The 
hyposulphite present is unaffected by cadmic carbonate, 
and consequently will be found undiminished in the fil¬ 
trate, where it can be readily estimated by the usual 
decinormal iodine solution. 
Werther’s method is preferable to the first process for 
several reasons. The cadmic sulphide washes with great 
rapidity, since, like argentic chloride, it has a tendency 
to coagulate into small clots; moreover, it has no in¬ 
clination to oxidize by exposure to the air. The substi¬ 
tution of a volumetric estimation in the case of the 
hyposulphite is likewise more expeditious, and in accu¬ 
racy perhaps excels the gravimetric method. I give the 
actual analyses more in detail. 
Estimation of the Sulphide. —About T5 gramme were 
dissolved in water, and excess of cadmic carbonate added. 
The reaction takes place almost instantaneously, without 
heat, and if the carbonate has been used in sufficient 
quantity, the cadmic sulphide separates perfectly. The 
sulphide was then collected on a filter, washed with hot 
distilled water and partially dried; then transferred to a 
small flask and oxidized with fuming nitric acid, the 
boiling was continued until the unoxidized sulphur had 
acquired a pure yellow colour, when the whole being 
allowed to cool, the sulphur was separated and weighed. 
The sulphuric acid formed was then estimated with baric 
chloride in the usual way. 
Estimation of the Hyposulphite. —A volume of carbonic 
acid -water was added to the filtrate from the cadmic 
sulphide precipitate, to convert the carbonates present 
into acid carbonates; decinormal iodine solution was 
then run in, till the blue colour appeared as indicated by 
starch paste. The value of the iodine solution being 
known as corresponding to crystallized soclic hyposul¬ 
phite, the equivalent quantity of anhydrous potassic 
hyposulphite was readily calculated. 
Estimation of the Sulphite. —But the estimation of the 
