together with its Analysis. 239 
Experiment 7.—The water that is contained in the Arragonite 
being chemically combined with the lime and carbonic acid, may 
occasion a closer union in those parts ; and this I have in some 
measure verified by taking the specific gravity of Arragonite 
after its desiccation. It proved to be 2.727 instead of 2.94, 
which was its original specific gravity ; and at the same time, by 
a similar mode, the specific gravity of Iceland crystal was 2.732. 
This near equality of specific gravity in the two bodies is sufli- 
cient to show that Strontian earth does not enter into the com- 
position of Arragonite, as has been lately advanced by a German 
chemist. ubi 
ANALYSIS. 
Some transparent crystals of Arragonite were reduced to powder, 
which was dried in the sun, to be certain of not overheating it. 
Twenty grains of this powder were weighed, and wrapped up 
in a clean thin leaf of platinum, that no part of it might be lost. 
The weight of the platinum was previously determined. The 
Arragonite thus folded up was placed on a plate of iron heated 
red-hot, and, after remaining in that situation for a short time 
without any of the carbonic acid being expelled, was carefully 
weighed in an excellent balance, and the inclosed substance was 
then found to have lost 0.16 grain of volatile matter, which has 
been already proved to be water. I made several experiments of 
this kind, but without observing any difference in the results. | 
The substance inclosed in the leaf of platinum was afterwards 
kept in the fire till it had acquired a dull red heat. The loss of 
weight, when accurately ascertained, — 0.25 grain. This addi- 
tional diminution of weight cannot, I think, be ascribed to a 
further loss of water, because in this experimenta thin piece of Ice- 
land crystal, which had been wrapped up together with the Arra- 
gonite, (but taken out before the deficit in weight was estimated,) 
and 
