EARTHS AND STONES. 
The nitric solution was evaporated to dryness: A 
reddish substance remained, which indicated the pre 
sence of oxide of iron. This substance was redissolved 
in water, and some ammonia mixed with it ; a reddish 
precipitate appeared, which, when dried, weighed 1, 
and was oxide of iron. The remainder of the solution 
was precipitated by carbonat of potass. The precipi 
tare weighed, when dried, 20, and possessed the proper 
ties of carbonat of lime. Therefore 200 parts of this 
mineral contain 20 of carbonat of lime, 1 of oxide of 
iron, and the remainder of the 33 parts he concluded to 
be water. 
The 167 parts, which were insoluble in nitric acid, 
were mixed with 500 parts of carbonat of potass, and 
7000 parts of water, and boiled for a considerable time. 
The solution was then filtered, and the residuum wash 
ed and dried. The liquid scarcely effervesced with a 
cids ; but with barytes it produced a copious precipi 
tate, totally indissoluble in muriatic acid. Therefore it 
contained sulphuric acid. 
The undissolved residuum, when dried, weighed 129 
parts. It dissolved completely in muriatic acid. The 
solution crystallized in needles; when dissolved in al 
cohol, it burnt with a purple flame : and, in short, had 
all the properties of muriat of strontian. Therefore 
these 129 parts were carbonat of strontian. Now, 100 
parts of this carbonat contain go of carbonic acid; there 
fore 129 contain 38.7. Therefore the mineral must 
contain in 200 parts 90. 3 of strontian. 
Now, the insoluble residuum of 167 parts was pure 
sulphat of strontian ; and we have seen that it contain 
* Jouv. de Min. No. XXXViI. I. 
131 
Chap.II.