1neath which is the sixth stratum,
likewise dark, but rough and three feet
thick. Afterward occurs the seventh stratum, likewise of dark colour, but
still darker than the last, and two feet thick. This is followed by an eighth
stratum, ashy, rough, and a foot thick. This kind, as also the others,
is sometimes distinguished by stringers of the stone which easily melts in
fire of the second order. Beneath this is another ashy rock, light in
weight, and five feet thick. Next to this comes a lighter ash-coloured
one, a foot thick; beneath this lies the eleventh stratum, which is dark and
very much like the seventh, and two feet thick. Below the last is
a twelfth stratum of a whitish colour and soft, also two feet thick; the
weight of this rests on a thirteenth stratum, ashy and one foot thick, whose
weight is in turn supported by a fourteenth stratum, which is blackish and
half a foot thick. There follows this, another stratum of black colour,
likewise half a foot thick, which is again followed by a sixteenth stratum
still blacker in colour, whose thickness is also the same. Beneath this, and
last of all, lies the cupriferous stratum, black coloured and schistose, in which
there sometimes glitter scales of gold-coloured pyrites in the very thin sheets,
which, as I said elsewhere, often take the forms of various living things.15
thick. Afterward occurs the seventh stratum, likewise of dark colour, but
still darker than the last, and two feet thick. This is followed by an eighth
stratum, ashy, rough, and a foot thick. This kind, as also the others,
is sometimes distinguished by stringers of the stone which easily melts in
fire of the second order. Beneath this is another ashy rock, light in
weight, and five feet thick. Next to this comes a lighter ash-coloured
one, a foot thick; beneath this lies the eleventh stratum, which is dark and
very much like the seventh, and two feet thick. Below the last is
a twelfth stratum of a whitish colour and soft, also two feet thick; the
weight of this rests on a thirteenth stratum, ashy and one foot thick, whose
weight is in turn supported by a fourteenth stratum, which is blackish and
half a foot thick. There follows this, another stratum of black colour,
likewise half a foot thick, which is again followed by a sixteenth stratum
still blacker in colour, whose thickness is also the same. Beneath this, and
last of all, lies the cupriferous stratum, black coloured and schistose, in which
there sometimes glitter scales of gold-coloured pyrites in the very thin sheets,
which, as I said elsewhere, often take the forms of various living things.15
The miners mine out a vena dílatata laterally and longitudinally by
driving a low tunnel in it, and if the nature of the work and place permit, they
sink also a shaft in order to discover whether there is a second vein beneath
the first one; for sometimes beneath it there are two, three, or more similar
metal-bearing veins, and these are excavated in the same way laterally and
longitudinally. They generally mine venæ dilatatæ lying down; and to
driving a low tunnel in it, and if the nature of the work and place permit, they
sink also a shaft in order to discover whether there is a second vein beneath
the first one; for sometimes beneath it there are two, three, or more similar
metal-bearing veins, and these are excavated in the same way laterally and
longitudinally. They generally mine venæ dilatatæ lying down; and to
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