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162
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DE NATURA FOSSILIUM
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where
it is fashioned into cooking vessels which are then bound with iron
hoops. The hard rocks should be dressed with iron tools as soon as they
are taken from the quarries since they become much harder after
standing in the air. These are used in making mortars in which
druggists compound medicaments and whetstones on which other stones
are ground. For these purposes they use the beds of rocks found in
Misena between Penica and the fortified city of Roseburg, as well as lapis thebaicus with yellow spots, chrysites from Chalazius, and basanites. The Ancients made mortars from these rocks and also from hard marbles, for example, the greenish marble from Ethiopia, from haematites, from each of the marbles of Taenarius, from Parian marble, Egyptian alabastrites, and from white ophites. Today
they make the small mortars used in grinding and pulverizing emery and
other hard stones from our jasper and onyx. Remedies for the eyes are
ground and mixed in mortars made from Ethiopian marble since this stone
itself, when pulverized on a flint, will destroy the mists that form in
front of the eyes.
There
are two other genera of rocks but square blocks are not cut from them.
One is called "fissile," the other "calcareous." The strata of
"fissile" rocks (slate) differ from those of other rocks in that they
can be split with ease. They differ in color since the former may be
white, yellow, red or some other color while the latter are either
gray, whitish gray, light or dark bluish gray, dark blue or black.
"Fissile" rock is found in many places but the very best with a dark
color, distinctly tabular form, and with golden veins comes to Lipsia
from Norinberg. "Fissile" rock will usually split in a fire and the
thin pieces produced in this way are used in Germany to cover churches
and large buildings.
"Calcareous"
rocks are so-called because lime may be produced from them when burnt
in a furnace. This genus varies in color. Some is white and the whitest
is found in the vicinity of the village of Bruno, especially in the
fields of Lichtenberg and even under the walled city of Wolfenbuttel.
Some is light gray or gray such as that about two miles from Chemnitz
on the road to Waldenburg. Some is dark blue as that from the lime
quarry of the village of Averswald five miles from Chemnitz. In the
mountains near Sala it is found white, light yellow and light red. A
rock that is part white and part light gray is found near the Moecheta
river not far from Pirna. The river is used to transport the rock to
the country along its course.
The
"calcareous" rocks are divided into hard and soft varieties. The rock
from near Bruno is soft and easy to work while that from Chemnitz is
hard. The Hanover variety is similar to Pirnian marble and when struck
gives a resonant sound similar to that of black copper chalcophones.
One of these stones in the walled city of Alcathea, Megara, gives a
tone similar to the cithara when struck with a pebble but this is
obviously due to the artificial carving. Although "calcareous" rock is
commonly dense the rock from Sala is loose-textured and full of small
holes. It has a variable unc-
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