384 On ALLANITE, a new 
). Tue folution of cerium in acetic acid is precipitated grey 
by infufion of nut-galls. Cerium is precipitated likewife by 
the fame re-agent from other acids, provided the folution con- 
tain no excefs of acid. This fact was firft obférved by Dr 
Wottasron, who communicated it to me laft fummer. I im- 
mediately repeated his experiments with fuccefs. 
c. CERIUM is not precipitated from its folution in acids by © 
a plate of zinc. In fome cafes, indeed, I have obtained a yel- 
lowifh-red powder, which was thrown down yery flowly. But 
it proved, on examination, to confift almoft ‘entirely of red 
oxide of iron, and of courfe only appeared when the folution of 
cerium was contaminated with iron. 
d. Tue folutions of cerium in acids have an aftringent tafte, 
with a perceptible fweetnefs, which, however, is different from 
the fweetnefs which fome of the folutions of iron in acids pof- 
fefs. 
e. THE muriate and fulphate of cerium readily cryftallife ; 
but I could not fucceed in obtaining cryftals of nitrate of ce- 
rium. } 
f. THE beft way of obtaining pure oxide of cerium, is to 
precipitate the folution by oxalate of ammonia, wath the preci- 
pitate well, and expofe it to a red heat. The powder obtained 
by this procefs is always red; but it varies very much in its 
fhade, and its beauty, according to circumftances. This pow- 
der always contains carbonic acid. 
g. I consiper the following as the effential characters of ce- 
rium. The folution has a fweet aftringent tafte: It is precipi- 
tated white by pruffiate of potath, oxalate of ammonia, tartrate 
of potafh, carbonate of potath, carbonate of ammonia, fuccinate 
of ammonia, benzoate of potafh, and hydrofulphuret of ammo- 
nia: The precipitates are re-diflolved by nitric or muriatic 
. acids : 
SR os 
