226 Analysis of the Substance 
3. Carbonate of ammonia formed also a precipitate in 
it. . . 
4. With oxalate of ammonia the precipitate is very light, 
and very minutely divided. 
5. The precipitate by the prussiate of potash is of a deep 
blue. 
We see that these preliminary experiments already give 
an approximate knowledge of the constituent parts of tur- 
quoise, but they are not sufficient to lead us to.a regular 
classification of it; for which reason, out of a large quantity 
of turquoises, I made choice of such as were highest coloured 
and hasdest, and I submitted them to the following experi- 
ments: 
A. 100 parts of turquoise reduced into powder were in- 
troduced into a small retort, and 300 parts of nitric acid at 
36° were poured upon them. In a short time a slight effer- | 
vescence took place, which continued until the solution was 
completed. The gas was collected by the hydrargyro-pneu- 
matic apparatus, and it presented all the properties of car- 
bonic acid gas. 
B. This nitric solution is white, and of a syrupy consist- 
ence; it was evaporated to dryness, and the matter remain- 
ing was afterwards made red hot in a platina crucible. 
Cc. Calcination scarcely changed its colour. 
This substance was again Hisealved in very dilute nitric acid, 
for the purpose of separating from it the iron which might 
have existed in it in the state of an oxide; but the whole 
was entirely dissolved ; which evidently shows that the iron 
was neither in the state of a red oxide nor as a’nitrate, but 
rather in the state of a phosphate. 
D. Ammonia in excess was poured into the liquor C, 
which gave an abundant white precipitate. After being 
washed and dried, this precipitate was treated with a strong 
solution of potash, which dissolved a certain quantity of it. 
The liquor was afterwards separated from the portion not 
dissolved, and muriate of ammonia was added, which se- 
parated a white matter from it that presented all the pro- 
perties ofalumine. This substance, after calcination, weighed 
a part and a half. 
E. The 
