dined angle of fourteen degrees, and all the fmaller rocks
of the hill have more or lefs the fame indination. We
ihall next fee, that a due obfervation of thefe circum-
itances, conftitutes a principal branch of the art of mining.
The ftone on thefe hills, as well on the fuperfices, as
in the centre, is of the fame nature as that o f Fontain-
bleau, and the pavement of Paris : on calcining it, and
examiningit minutely, when it comes out of the furnace,
the grains o f fand are found to be of the fame ihape and
tranfparency with thofe on the fea ihore. The enormous
pieces of rock which compofe the internal part o f the
mountain, are cut with vertical fiifures, and though the
rocks feem to have an ered pofition one over the other;
the length of the hill, this is not the cafe, for they all incline
to the fouth.
Two veins, more or lefs impregnated with cinnabar,
cut the hill almoft vertically, and form thofe ftrata which
we have faid were from two to fourteen feet broad ;
thefe unite on the moft convex part of the hill, ftretch-
ing as far as one hundred feet, from which happy union
arofe that prodigious richnefsof mineral called delRofario,
whioh has given many millions of quintals of quickfilver,
and was in my time the occafion o f that difmal fire in
the mine.
A bed
A bed of rock two or three feet broad, runs from north
to fouth, acrofs the hill, and cuts the two veins, fo that
further on, there is no appearance of cinnabar. This
kind of rock being prior to the forming o f the ore, ftops
the mineral vein, which finding it fo hard, cannot penetrate
that way, and is obliged to turn out of its dired
oourfe. It is from this rock to the other extremity of the
mine, that I faid I went in fourteen minutes. I f the
veins ran without interruption, and always on a ftraight
line of the fame breadth, lefs trouble and art would be
neceflary in the working of mines. Let us now fpeak o f
the method of working thefe o f Almaden before my arrival
there.
The miners had never funk their ihafts according to
the inclination of the vein, but had made them perpendicular,
letting themfelves down by pullies in buckets,
from which awkward contrivance arofe all the mifchiefs
that followed, for in proportion as they went deeper,
they often loft the vein, and were obliged to open a new
ihaft with the fame inconveniences, and thus went on,
continually encreafing their ihafts and galleries with
fimilar defeds, by which they not only loft a great deal
o f labour and time, but were deprived of a free circulation
of air underneath, as that which ruihed in at
one part, immediately made its efcape at the other,
next to it, and the people were fuffocated below ; the
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