80 J. W. Mailet on Schrétterite from Alabama. 
blue color. The water collected on the sides of the tube has a 
slight acid reaction. Heated alone before the blowpipe on char- 
coal, it becomes white and arn Ee aes quietly ; on a 
d, an 
fectly i in Riosions acid, the solution, if concentrated, pees 
izing on cooling. Becomes by strong ‘ignition very difficult of 
solution in acids. 
= analyses were made of the mineral, with the following 
results :-—. 
Sas 2» Mean. Atoms. 
cma oy 
Silica, 10°35 10°72 10°53 232 1 
Alumina, 46°80 46°16 46°48 
Water, . 4112 41:07 41°09 4565 19-7 
Oxyd of zinc, 74 7 4: 
pee ee te, ‘ traces. traces. traces. 
Magnesia, 
_ Sulphuric acid, 83 a. 80 
99°84 99°51 99°67 
Hence the formula #14 Si+-20H. 
The mineral differs essentially from schrotterite, to which 
the formula 414Si+18H has been assigned, only in operon aed two 
atoms more of water; and since all the physical ropert 
closely with those of the species described by Se Schrdtter, t the #6 two 
may be fairly considered as identical. In the analysis of Schrit- 
ter, as I have seen it quoted, no mention is made of the temper- 
ature at which the mineral was dried, or whether it was dried 
at all, and the course pursued in this Leaick might perhaps ac- 
count for the difference in the quantity of water, the material 
my experiments having been taken in its natural con- 
dition. In each of the two determinations of water, an attemr 
was made to ascertain the eee lost at 100° C. but with- 
out very accurate result. ‘The mineral begins to give off water 
below w 100°, and at 100° pretty ner loses 8 or 10 p.¢., but 
jues slowly to yield a little more fora long time at this 
ure, so that, weighed hour by hour, it still at the end of 
hours decreased in weight a few milligrams each time 
vas. paieced upon ate Cee At higher temperatures 
seems to be in ay gradually driven off, and 
