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ON SULPHURIC ACID. 
ART. XLV. — SULPHURIC ACID CONTAINING ARSENIC. 
In the Repertory of Pharmacy of Buchner, M. Wack- 
roder,* has drawn the attention of chemists to an acid called 
English sulphuric acid, but which is probably from Bohemia, 
and is actually to be extensively found in commerce. This 
acid contains, besides sulphate of lead, considerable arsenic 
acid. It is likewise announced that this article cannot be 
used as the means of obtaining pure hydrochloric or rectified 
sulphuric acid; and in consequence of the alteration produced 
in these acids by the arsenic contained in it, it should be re- 
jected in their preparation. It has since been noticed, that it 
will not answer in the preparation of pure nitric acid, and 
sulphate of zinc, in the disengagement of hydrogen gas, or in 
general for any chemico-pharmaceutical agent. 
New trials have confirmed him in the truth of these opi- 
nions; they have demonstrated to him the frequent alterations 
produced in phosphorus by the presence of arsenic. The 
facts communicated by MM. Barweld and Wittstork, (Jar- 
buche fur die Pharmacie,) came under his notice during his 
researches. According, to the experiments of this chemist, 
he used, together with M. Muller, a sulphuric acid containing 
arsenic, and was not able to obtain from bones phosphoric 
acid exempt from arsenic, even when this phosphoric acid was 
purified by means of alcohol. On saturating this acid by car- 
bonate of soda,all the arsenic passed to the soda and remained 
in combination with it, principally in the last crystals obtained 
from the solution. Phosphates free from arsenic cannot be 
formed with such an acid, except it be previously purified by 
sulphuretted hydrogen. An examination of the phosphate of 
soda of commerce, appears to us very necessary, as in many 
shops a phosphate has been found which was rendered impure 
by the presence of arsenic. Likewise the chemists of Berlin 
have found arsenic in phosphorus. Phosphoric acid pre- 
pared from phosphorus, by nitric acid, will always contain 
* Journ. fur Pract. Chemic. • 
