CLARKE 
STEIUER 
.^ D ] CONSTITUTION OF CALAMINE AND ANALCITE. 
19 
gas, and gained perceptibly in weight. The percentage data, reckoned 
on the original calamine, were as follows, in two experiments: 
[i. 
Gain iu weight ... 6.00 6.43 
SiO, soluble in Na 2 CO :i 16.45 20.95 
Sulphur in residue 24. 12 
Complete conversion of calamine into 2ZnS + Si0 2 implies a gain in 
weight of 5.80 per cent ; and it is therefore evident from the figures of the 
second experiment that the limit of change was approached very nearly. 
The 24.12 of sulphur taken up is quite close to the 26.53 per cent which is 
required by theory. About eight-ninths of the calamine had undergone 
complete transformation. Again, no definite fractionation was detected. 
The hydrogen sulphide reaction was examined still further with 
reference to the temperature at which it becomes effective. Even in 
the cold calamine is slightly attacked by the gas, but its action is unim- 
portant until the temperature of 400° is approximated. Then it becomes 
vigorous and the reaction goes on rapidly. A few experiments with 
willemite showed that it also was attacked by hydrogen sulphide, but 
less vigorously than calamine. 
Analcite. 
Analcite, from many points of view, is a species of peculiar interest, 
and of late years it has received a great deal of attention. Its formula 
may be written in various ways, especially as regards the interpreta- 
tion of its one molecule of water; but evidence too often has yielded 
before preconceived opinion. Additional evidence is now available, 
partly from the experiments of Friedel and partly from the data 
obtained during the present investigation. 
The analcite examined by us was in well developed crystals from 
Wassons Bluff in Nova Scotia. A uniform sample was prepared as usual, 
and the analysis given below is contrasted with the theoretical compo- 
sition required by the accepted empirical formula NaAlSLO^ ILO. 
Analysis. 
Found. 
Calculated. 
Si0 2 
57.06 
LM.4X 
.13 
.16 
12. 20 
. 58 
8.38 
99.99 
54.55 
23. 18 
A1 3 3 .. . 
Fe 2 i 
CaO 
Na 2 , 
L4.09 
H 2 at K)(i 
H7O over 100 
8.18 
100. HI) 
