262 Brush and Dana—the Spodumene of Branchville, Conn., 
tion ; there are, however, other facts which have an important 
bearing upon this point. 
It was found by Mr. Penfield that, although the mineral 
gelatinizes with acid, it is not entirely decomposed. On the 
contrary, it is divided into two portions by the treatment with 
hydrochloric acid, viz :—a soluble portion (A), and an insoluble 
remainder (B), the latter including also the silica extracted from 
the soluble part. The results of three analyses gave 
B. Insoluble in HCl, with 
A. Soluble in HCl. SiO. from A. 
No. 1 (17°97) : 82:03 = 100- 
2 16°65 83°01 = 99°66 
3 17°91 82°18 = 100-09 
In the case of No. 2, complete analyses of both the soluble and 
insoluble portions were made; these were independent of the 
total analyses of the same sample already given. The method 
of analysis was, briefly, as follows:—-A gram of the mineral 
was digested with HCl, evaporated to dryness, then moistened 
with HCl and a second time evaporated to dryness. After 
being again moistened with HCl the soluble portion, A above, 
was filtered off and the alumina and alkalies determined in it 
by the usual methods. The insoluble portion, which included 
the silica extracted from A, after being weighed, was boiled 
with Na,CO, and (in the case of No. 3) with a little KOH. By 
this means the soluble silica of A was dissolved out and the 
insoluble remainder being weighed, the amount of the soluble 
silica was determined by the difference. Finally, the insolu- 
ble part was analyzed in full by the usual methods. The 
results of the analyses were as follows: 
No. 2. 
B. Insoluble in HCl with silica of A 83°01 
nsoluble remainder after treatment with soda 67°56 
15°45 
A. Soluble in HCl (16-65), plus silica extracted by soda from B 32710 
_The two parts, therefore, into which the original mineral is 
divided by hydrochloric acid, are :— 
No. 2. 
A. Soluble portion 32°10 
B. Insoluble portion 67°56 
99°66 
The composition obtained for A was as follows :— 
A, Soluble ion. 
Calculated to 100. Calculated from formula. 
0. 2. No. 2. 
SiO. 15°45 48°13 4751 
Al,Os; 13°00 40°50 40°61 
Li.O 3°50 10-90 11°88 
0715 047 ae 
