veins of various directions, as reprefented
at P. In thefe mines it is neceffary to arch
the roads with ftone; for after long rains,
wood is not capable of Attaining the
weight. The fluor in various places appears
to have been formed on the limeftone ; for
it frequently has that fubftance for a nucleus,
around which it feems firft to have
chryftallized, till it had greatly increafed by
accumulation. Frequently, however, the;
centre is hollow.
In various parts of the mine, in caves,
filled with clay and loofc adventitious mat-*
ter, the fi'uor appears in detached mafles,
bearing every appearance of having been
broken from the limeftone, on which, it
feems to have been originally formed j for
every piece, in one part or other, feems to
have adhered to fomething, and to have
been broken off, Thefe caverns are frequently
qu.ently befet with beautiful calcareous fta-
ladtites, of a large fize.
It is impoffible to account for the prodigious
variety, and Angular difpofition of
the veins,, and fudden contrails of the fineft
colours, which occur in this fubftanpe. Some
of the pieces of fluor are a foot in thick-
nefs, and have four or five different and.
diftind veins; but fuch large pieces are very
rare. In general they are only about three
qr four inches thick; and fome prefent png
ffrong vein, while others ihew many finaller.
Such as difplay a geographical figure, like
a coloured map, are mpft rare, and valuable.
Some varieties are. much more loofe i,n their
texture than others. The colouring matter
has been generally thought to be iron,, bpt
I fufpe.4 it to be afpbahy which may perhaps
contain pyrites in a dqcampofed ftate;
but there are many Angular varieties which
have not undergone any anal yAs. The
F 4 fluoric