Chemical Analyses. 229 
a long time even in sulphurous acid, and without the latter losing 
its peculiar smell. When the rosacic acid is dried, which has 
been in contact with the sulphurous acid, it yields a very fine 
earmine colour. When nitric acid at 32° is poured on the ro- 
sacic acid, there is immediately a considerable swelling up, and 
a brisk effervescence of nitrous gas; the red powder disappears, 
and a yellowish white substance is formed. On boiling the li- 
quor, the whole is dissolved, and there remain, by a slow evapo- 
ration, red scales periectly similar to those which are obtained 
by treating the uric acid with nitric acid. According to M. 
Proust, by pouring nitric acid on this acid a considerable quan- 
tity of carbonic acid gas is liberated. Since the nitric acid only 
ean produce such an effervescence, the extrication of the car- 
bonie acid and of the nitrous gas cau only be ascribed to a reci- 
procal decomposition which the rosacice acid and the nitric acid 
exercise on each other. The simple muriatic acid does uot ap- 
‘pear to have a sensible action on the rosacic acid; the powder 
remains in it diluted, without losing its intensity of colour, and 
it is only after a few ‘days that it becomes fawn-coloured. ‘The 
oxy-muriatic acid discolours the red colour very speedily, and 
makes it yellow. 
“¢ Water charged with sulphurated hydrogen has no kind of 
action on the rosacic acid. These two substances may remain 
together for fifteen days without undergoing any change. Never- 
theless, after a longer time the red powder disappears entirely, 
and the liquor acquires a putrid ammoniacal smell. 
** When we sprinkle the rosacic acid with a concentrated so- 
lution of caustic potash, the powder immediately acquires a 
brownish colour, and abundance of ammonia is liberated. This 
combination of rosacic acid and of potash is very soluble in 
water. 
“The acids precipitate from it a powder ofa yellow colour; and 
it would seem as if the rosacic acid by its union with potash had 
already undergone a kind of decomposition ; at least I have not 
been able to reproduce it by means of an acid with its primitive 
red colour. Liquid ammonia left in contact during some hours 
with the rosacic acid converts it into a fme yellow powder. The 
ammonia is combined in this yellow powder in the state of salt 
with the rosacie acid, and this salt is more soluble in water than 
the rosacic acid itself. The rosacie acid is precipitated in a yel- 
‘tow powder from the aqueous solution of this salt with a base of 
ammonia. On sprinkling the rosaci¢ acid with a concentrated 
solution of nitrate of silver, the powder loses its colour in a few 
hours and becomes bottle green. The pure nitric acid diluted 
in a solution of nitrate of silver also assumes after some time a 
brownish aspect. The nitrate of mercury and muriate of tin 
P3 produce 
