22 
CONTRIBUTIONS TO CHEMISTRY AND MINERALOGY. 
[BULL. 167. 
A. 
B. 
C. 
D. 
Average. 
Residue. 
Sol. SiO- 2 
1.20 
2.03 
54.96 
21.37 
.16 
9.57 
7.12 
2.21 
1.89 
1.61 
54. 96 
21.37 
.16 
10.44 
7.12 
2.15 
2.04 
62.59 
24.34 
.18 
AL 2 Ot . 
CaO 
NaCl 
Na,0 
11.26 
10.50 

8.11 
2.46 
2.32 
NHt 
2.03 
2.25 
2.19 
2.00 
H 2 
99.31 
99.85 
100. 00 
The analcite residue, like the original mineral, is completely decom- 
posable by aqueous hydrochloric- acid. It may be a mixture, but it 
seems more probable that it is a definite compound, for it approximates 
in composition to the formula 
H 2 Na 2 Al4Si 8 0, 4 . NH : >. 
This represents a quadrupled analcite formula, in which hal J of the 
sodium is replaced by hydrogen, and with NH 3 in place of 4H 2 The 
analytical comparison is as follows: 
Found. 
Calculated. 
SiO, 
62. 59 
24.34 
.18 
8.11 
2.32 
2.46 
61.46 
26.12 
ALO> 
CaO 
Na 2 
7.94 
2.30 
2.18 
H,0 
NH 3 
100.00 
100. 00 
The agreement is not close, but it is close enough to be suggestive 
and to indicate the character of the reaction which has taken place. 
It needs, however, verification by additional experiments upon other 
preparations, and upon analcite from other sources. In this connec- 
tion it may be well to reiterate that the substance was prepared by 
very long heating at 350°, and is therefore stable at that temperature. 
An interesting feature of these experiments is their harmony with 
the researches of G. Friedel, 1 who has shown that the water of zeolites 
may be replaced by ammonia and other substances, without change of 
the crystalline structure. In the case of analcite, ammonia was taken 
up to the extent of 2.04 per cent, or almost exactly the amount found 
Bull. Soc. Min., Vol. XIX, 1896, p. 94. 
