evidently remain with the silica in the form of sulphate of ba- 
contains ‘dete lime, on account of the insolubility of its sulphate. 
This last difficulty is however obviated, in some degree, by the 
very considerable solubility of sulphate of lime. in. hydrochloric 
- acid, a fact which must havé been noticed by many chemists: 
Po 8 an 
fete Se Satie, ES 
colorless transparent orthéclase from New York island. This 
feldspar was fused with chlorid_of barium, sous to the above 
et ee soda, to be perfectly pure. 
h 
S hornblende, from Franconia, New Hampshire. e silica 
tained from this was found to contain ,considerable more than’a 
_ trace of iron. Ido not therefore venture to recommend this pro- 
_ oxyd of iron. Many more experiments which time has not per 
Initted me to make, will soon be me to settle this question, 
which I do not consider, yet determined. 
To test the chlorid of barium reel quantitatively, the min- 
eral called pink scapolite, of Bolton, Mass., long ago analyzed by 
Dr. Jackson, was selected. My results agree entirely with his, 
except as regards the presence of lithia and oxyd of cerium, 
which careful Sri examination did not enable me to 
aie 
cal. w s found, contrary. to recorded statements, bid 
a be ee ee ph sed by concentrated acids, even w 
finely elutriated. -A determination of the silica, made by i 
composition with hydrochloric acid, gave the per-centage 5025 ; 
- @Mother, made by fusion with carbonate of soda, gave 47: 
...T'wo determinations of the specific gravity, made u upon the 
coarse powder, gave the numbers 2:7002 and 27046 
The results ‘9 fa fusion with chlorid of barium were as follows: 
ee Oxygen. 
MIR 0c 4 xh Sk MEDS 24-78 24-78 
Alumina, é , pon COTE st = 40-71 
Peroxyd of iron, . ey 68 § 
CaaS i ar bs AS2 on 
NN i secs. wsins opty ROM 2-26 
Protoxyd of manganese, race. 
100°77 
Agreeing nearly with the received formula of scapolite— 
Ga Na)* Si?+-2Al Si, 
which requires for the oxygen of the protoxyds, peroxyds and 
New method of decomposing Silicates. 325 
When the mineral thus iniated contains sulphurie acid, it will : 
ryta. culty would also seem to occur when the mineral © 
e first qualitative experiment was made with a specimen of 
process, and the silica thus obtained was found, upon fusion with” 
xt experiment was made upon a black crystallized. 
af 
ye 
