422 Progress of Foreign Science. 
Sulphuric acid dropped into it produces sulphate of barytes, 
and the powerful acids develope immediately in it a very lively 
odour, resembling that of the pure acetic acid. He wished to 
know if the body which was thus rendered sensible to the 
smell by means of acids, would become manifest also with other 
bases. He, consequently, mixed the solution of the barytic salt 
with sulphate of potash, in the proportion for precipitating all the 
barytes, and he obtained, by evaporating the liquid, long nee- 
dies, which were powerfully coloured by azotized carbon, and 
which yielded, with the acids, the odour above described. 
Similar results were obtained with salts of soda and ammonia. 
The barytic salt precipitates in a white powder the nitrates 
of mercury, silver, and lead ; the nitrate of copper, in a greenish 
brown; and the chloride of gold, in a brownish yellow. It does 
not precipitate the chlorides or perchlorides of iron and tin, nor 
the perchloride of mercury. 
There is, then, evidently produced, when water of barytes 
absorbs cyanogen, a peculiar body, which saturates the bases 
as anacid; and it appears, in fact, that cyanogen comports 
itself like chlorine with alkaline solutions ; that the water is 
decomposed, and that there is produced a hydrocyanate and a 
cyanate. For the sake of simplicity, he distinguishes by the 
name of cyanic acid, the body which he has obtained combined 
with barytes. 
Every time that we evaporate the solution of an alkaline cy- 
anate, there is formed carbonate of ammonia; which is the 
reason why the cyanate of barytes is always mingled with car- 
bonate, and why carbonate of ammonia sublimes when we heat 
an insoluble cyanate imperfectly dried. 
The Editors of the Annales de Chimie, after giving the author’s 
memoir, observe, in a note, that his experiments leave the ex- 
istence of the cyanic acid undecided ; and one might ask him, 
why, after having recognised so penetrating an odour of vinegar, 
when he poured an acid on his pretended cyanate, he did not 
seek to collect the body which produced this smell. It would, 
perhaps, be possible, in operating at a very low temperature, and 
in decomposing the salt of barytes by sulphuric acid, in another 
solvent than water, to obtain the new acid insulated. 
On anew Acid produced by the Distillation of Citric Acid. By 
J. L. Lassaigne®, 
When citric acid is put to distil in a retort, it begins at first 
by melting ; the water of crystallization separates almost entirely 
from it by a continuance of the fusion, then it assumes a yel- 
lowish tint, which gradually deepens. At the same time there 
is disengaged a white vapour which goes over, to be condensed 
* Journ. de Pharmacie, Oct. 1822. 
