ON THE FORMATION OF HYDROCYANIC ACID, ETC. 41 
ART. XIII.— ON THE FORMATION OF HYDROCYANIC ACID 
IN THE PREPARATION OF SPIR1TUS iETHERIS NITRICI. 
By Mr. William Bastick. 
In Germany, it is customary among Pharmaceutists to use 
sugar or starch in conjunction with nitric acid for the de- 
velopment of hyponitrous acid, in the preparation of spiritus 
aetheris nitrici — a practice recommended by Liebig, and de- 
scribed by Dr. Pereira in his excellent work on Materia 
Medica. 
An Apothecary of Berlin was led to believe, that hydro- 
cyanic acid was generated in the spiritus aetheris nitrici, from 
the peculiar odour which it possessed when prepared in this 
manner. 
At the suggestion of Professor Liebig, I undertook to ex- 
amine the fluid obtained by this process, to see if the above 
surmises were correct ; and I succeeded, by the most un- 
equivocal tests, in showing the presence of hydrocyanic acid 
in it, especially when the receiver was kept sufficiently cool 
to admit of its condensation. I then estimated it quantita- 
tively by precipitation, with a salt of silver, which gave, as 
the mean of three experiments, a precipitate of cyanuret of 
silver, of about one grain, which* is equal to nearly one-fifth 
of a grain of anhydrous hydrocyanic acid in one hundred 
grains of spiritus aetheris nitrici, that being the quantity 
operated upon. 
I endeavored to produce hydrocyanic acid by the substi- 
tution of oil of turpentine, a substance highly rich in carbon, 
in the place of alcohol, by this process, but did not obtain a 
trace of the acid. I have since examined the spiritus aetheris 
nitrici, prepared according to the London Pharmacopoeia, 
but did not succeed in obtaining the slightest indication of 
the presence of hydrocyanic acid. At present, I have not 
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