9 
some Minerals of the Zeolite Family ^ 
Silexj. 
38.30 
Contains of Oxygen, 19.26 
No. of Equivalents, 16 
Alumine, 
30.20 
14.10 
12 
Lime, 
13.54 
3.76 
3 
Soda, 
4.53 
1.16 
1 
Magnesia, 
0.40 
Water, 
13.10 
ir.55 
10 
100.07 
This mineral contains only traces almost imperceptible of pot- 
ash. The alumine which I obtained from it, when precipitated 
by ammonia, presented a phenomenon which I had not observed 
before, and with which I was much struck. After having weigh- 
ed it, I introduced it into a phial where there were some drops 
of moisture. The phial became warm. I then heated the 
phial, to volatilise the moisture, and when the alumine was en- 
tirely cooled, I allowed some drops of water to fall upon it, 
when it again became warm. I supposed that this effect was 
produced by a little lime in the alumine, but I could not find 
any foreign substance, excepting a very small quantity of mag- 
nesia. I next prepared a mixture of alumine and magnesia, 
nearly in the same proportion, and I found that when these two 
earths are precipitated together, they acquire the property of 
heating one another, when, after drying them in the fire, they 
are moistened with water, — a property which neither of them 
possesses in an insulated state. When we dissolve the alumine 
which contains the magnesia, it forms at last a white powder, 
which appears insoluble in acids, and which appears to be an 
aluminate of magnesia ( Spinelle ). By boiling the solution for 
some time, it is at last completely dissolved. 
The formula which expresses the composition of Thomsonite 
is NS 4- SCS 4- 12^ A 4- As there are Paranthmes 
which contain soda, we may say that Thomsonite is s. Par an- 
thine with water of crystallisation. We are, however, still ig- 
norant of the ratio of the lime to the soda in the paranthines 
which contain the latter. 
5. The fnineral sent by Mr Allan under the name of Cha- 
hasie^ but without a locality, has been analysed by my friend 
Mr Arfwedson, who found it to consist of 
