88 
Dr Gm el in's Analysis of Finite 
Two different analyses of pinite have already been made 
known ; the one by Klaproth, of pinite from the Pinistollen, 
the other by Drapier, of pinite from Auvergne. They found 
it to consist of the following ingredients : 
Klaproth. 
Drappier. 
Silica, 
29-50 
46.0 
Alumina, 
63-75 
42-0 
Oxide of Iron, 
675 
2-5 
100 00 
90-5 
Klaproth himself seems not to have put much confidence in his 
analysis, which was made at an early period, as he has not ad- 
mitted it into his contributions. The mineralogical affinity 
which was presumed to exist between pinite and mica, having 
thus received no confirmation from chemistry, I imagined that a 
repetition of its analysis would not be superfluous. For this 
investigation, I made choice of the pinite of St Pardoux, it being 
the only kind I could procure in sufficient quantity. 
Its specific gravity was found = 27575 4- 6<| R. It is assert- 
ed in almost all mineralogical works, that the pinite cannot be 
melted before the blowpipe : this assertion is founded upon the 
examination of Klaproth, made upon the pinite of Pinistollen. 
I have had no opportunity of examining that variety under the 
blowpipe ; but the pinite of St Pardoux melts on the edges in- 
to a glass full of blisters, when thin splinters of it are presented 
to the flame, although it does not melt into a globule. 1 have 
observed in general the same reactions as those which have been 
described by Professor Berzelius, in his Treatise on the Blow- 
pipe ; and I have only one circumstance to add, which, in so 
far as regards the geological relations of pinite, seems to deserve 
some attention. The pinite, when heated in a glass phial, gives 
out water of a disagreeable empyreumatic smell, which instantly 
blues reddened litmus, and therefore contains ammonia. It 
cannot be determined whether this ammonia is ready formed in 
the mineral, or is rather a product of the decomposition of some 
animal matter contained in it : the latter, however, would seem 
to be the more probable conjecture. It may be observed, that 
pinite never occurs in fresh rocks, but always, as for instance, 
in Auvergne, in a decomposed granite, upon which the volcanic 
mountains of that country rest ; and upon this occasion I beg 
