n
fluoric acid is eafily obtained by pulverizing
the fluor, and putting it in a leaden retort,
to which add its weight of any of the mineral
acids. Apply a gentle heat, and the
fluoric acid will appear as gas, which may
be caught in a veffel o f the fame materials
with the retort. Its peculiar property of corroding
glafs and filiceous fubftances, is well
known, and has been employed in France
in engraving glafs plates of Angular beauty.
It is alfo a noted flux for the. lead ore, its
very name being derived from its being fo
ready a mean of accelerating fufion.
Faujas de St. Fond has pronounced this
fubftance to be the. moft beautiful in the
mineral kingdom; and has particularly
praifed the elegance of the manufacture. *
In the Joofe earth of the caverns are found
rounded nodules of lead ore, fometimes
called potatoe ore; and there is in the fame
mountain a pipe vein of calcareous fpar,
one
n
one of which contained lead ore, which
was worked as at M, called the Miller mine.
The limeftone that compofes the whole is
full of marine exuviae. This mountain,
jas I before obferved, reaches fouthward to
the Winnets, where it is feparated from the
Long Cliff by a deep ravine, in which is
the road to Manchefter.
The rocks on the fide of the road are
ftupendous, and in many places perpendicular,
running in all directions, and forming
immenfe caverns. The mines of this mountain
afford the greateft variety of mineralo-
gical information of any which I have yet
feeri. The veins themfelves, the frequent
obftruCtion of their directions, and the difr
location of the ftrata, with the heterogenous
fubftances" found in the immenfe caverns,
prefent matter for great ftudy, and curious
obfervation.
The accefs into the mine of fluor is tolerably