10 M. Berzelius on 
the Chemical Composition of 
Silex, 
49.07 Contains of Oxygen, ^4.68 No. of Equivalents, 
8 
Alumine, 
18.90 
8.83 
3 
Soda, containing ) 
a little Potash, i 
12.19 
3.11 
1 
Water, 
19.73 
17.55 
6 
The presence of potash in the soda, makes it appear that there 
is a small excess of this last. The formula, which expresses 
the composition of this mineral is then ^^2 r + ^ 6 Aq-, 
the first term of which will require some explanation. When 
it appears that a small quantity of one base replaces a portion 
of another that is wanting, without its appearing that this re- 
placement is made according to chemical proportions, we con- 
sider it as purely mechanical, and arising from the isomorphous 
nature of substances crystallised together. In this case we 
make a single term of the substances which are supposed to 
replace one another mutually, by setting the one above the 
other, the sum of the oxygen in the two bases being thus taken 
as the oxygen of the single one. This stone is composed of 
fixed elements, precisely like Analcime, from which it differs 
only by a triple proportion of water, and in which M. Arfwed- 
son has also found potash mixed with soda- As a point of com- 
parison, M. Arfwedson has analysed also the primitive chabasie 
of Fassa, which was given me for analysis by M. Haiiy. It is 
composed of 
Silex, - 48.38 Which contains of Oxygen, 24.37 No. of Equivalents, 8 
Alumine, 
19.28 
9.00 
Lime, 
8.70 
2.44 
Potash, 
2.50 
0.43 
Water and Loss, 21.14 
18.81 
100.00 
The formula which results from this analysis is f 
q- 6 Aq, You see, then, that the kind of combination is the 
same among these minerals, but that the one contains soda, 
whereas the other contains lime, a difference analogous to that 
between Scolezite and Mesotype. 
I shall add here the results of an analysis, which I made 
some years ago, of Chabasie^ found in a primitive mountain at 
Gustafsberg. It contained 
