Chemistry and Chemical Arts. 123 
pungent acid taste, becoming astringent. It reacts strongly upon 
turnsole. Exposed in solution to the air, it grows brown, and gives 
rise to apocrenic acid. It is soluble in water and in absolute alcohol, 
inevery proportion. Its salts with the alkaline bases, resemble ex- 
tracts; andare insoluble in absolute alcohol, but become more and more 
soluble in it, in proportion as it contains water. ‘The ammoniacal 
salt becomes acid during evaporation. ‘These salts become brown 
very soon from the action of the air, converting them into apocre- 
nates, which may be easily separated by means of gelatinous alumi- 
na. The crenate of potash yields carbonate of ammonia by distilla- 
tion. The crenates with an alkalino-earthy base are also slightly so- 
luble in water, and dry in a layer, like varnish. The crenic acid 
precipitates the acetate of lead of a slightly yellowish color, and the 
acetate of copper of a clear green color ; it yields a soluble salt with 
the protoxide of iron, and an insoluble one with the peroxide, but 
which dissolves in ammonia. It precipitates also the neutral sul- 
phate of iron, the precipitate bemg of a whitish, or greyish red. 
The nitrate of silver gives likewise, a precipitate which soon becomes 
purple, and is perfectly soluble in ammonia. If only a small quan- 
tity of the nitrate of silver is added to the crenate of potash, the 
precipitate does not appear, because a double salt is formed. 
The apocrenic acid is brown and resembles a vegetable extract ; 
its taste is purely astringent ; it is slightly soluble in water, but dis- 
solves in a solution of crenic acid; it is more soluble in absolute alcohol 
than in water, although the alcohol does not act immediately upon 
it. It is almost entirely precipitated from the aqueous solution by 
the ammoniacal salt in flocculi of a deep brown color, resoluble in 
an abundance of water. Its compounds with the alkalies are per- 
haps neutral, of a brownish black color, resembling extracts, and in- 
soluble in alcohol. It expels acetic acid from its combinations ; it is 
more soluble likewise, in a solution of acetate of potash, which ac- 
quires by it the property of reddening turnsole. ‘The ammoniacal 
salt acquires also this property by evaporation. ‘The salts of baryta, 
of lime and of magnesia are very slightly soluble. 'The earthy and 
metallic salts are in general insoluble, with the exception of that 
formed by the protoxide of iron. The salt of oxide of copper dis- 
solves little by little in washing ; the solution has a metallic taste and 
leaves on evaporation a brown varnish. ‘The apocrenic acid con- 
tains nitrogen like the crenic acid. 
These two acids are produced by the decomposition of vegetable 
substances. ‘The crenic acid and an acid resembling the apocrenic, 
