156 
MISCELLANY. 
4 
on a watch-glass a very bitter white powder, which gave the bright red 
reaction with cold concentrated sulphuric acid. 
If from 50 to 60 grms. of water be added, the liquid remains opake, 
apparently without any precipitate resulting ; but after some time, one 
is observed to form with the gelatinous appearance of a precipitate of 
hydrate of alumina, which it is far more difficult to collect. It is conse- 
quently important to add the water in small portions, and to cease when 
it is seen that the precipitate separates with facility. — Ibid, from Journ. 
thim. Med. 
On the Purification of Commercial Nitric Acid. By M. C. Barres- 
wil. — Commercial nitric acid almost always contains hydrochloric acid, 
which it is frequently important to separate. The usual method for ef- 
fecting this, consists in adding a slight excess of nitrate of silver to the 
nitric acid, and distilling. However convenient this process may be, it 
is always employed with ragret ; for although the loss in silver is theo- 
retically naught, it practically amounts to a pretty considerable quantity 
in a laboratory in which much pure acid is employed. For this reason 
I thought it might be useful to indicate a very simple method for ob- 
taining pure nitric acid without the employment of nitrate of silver. It 
consists in distilling the commercial acid, and setting aside the first 
portions, amounting to from one-fourth to one-eighth, according to the 
quality of the acid employed. This first product is very impure, and 
may be turned into nitro-muriatic acid ; that which passes over subse- 
quently is absolutely pure. — Ibid, from Journ. de Pharm. 
On a means of detecting Quinic Acid. By John Stenhouse, Ph. D. — 
As it is a point of considerable importance to be able to distinguish the 
true Cinchona barks 'from the spurious, Dr. Stenhouse offers, in the 
present communication, a means of effecting this through the medium 
of the quinic acid, which is always present in the genuine Cinchonas. 
The process proposed consists in converting the acid into quinone by 
means of sulphuric acid and peroxide of manganese, and submitting 
the mixture to distillation, when the quinone, with its strongly-marked 
characteristic properties, passes over. Less than J oz. of the sample of 
bark is sufficient for the trial. In operating on spurious barks, the al- 
burnum of the Pinus sylvestris, the latter being stated, on the authority 
of Berzelius, to contain a ^ per cent, of quinate of lime, and also in 
cases when quinic acid is said to be associated with gallic acid, — the 
author could not trace its presence, even when operating on 1| lb. of the 
material, although on adding 2 grs. of quinate of lime, the quinone was 
immediately traceable. The author also states that the presence of an 
