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BOOK V
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107
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in
Hesse. Some stones are given a square form after quarrying, for example
the Naxian stones from the marble quarries and the stones from the
Armenian quarries. Recently a few water stones have been fashioned into
triangular shapes about six inches long. These are found near the
Krakow fortress in Bohemia and consist of wood that has been turned
into stone. Only the largest blocks are shaped into the form of a drum
and used with water to sharpen tools, being turned either by a water
wheel or by a man. Mill-stones are made from large and hard blocks.
Some are made from the black and white banded rocks brought from Lower
Germany and from the stones that have the appearance of broken bones.
These latter are called ίνούοωτ by the Greeks. All of these
stones can be used to sharpen iron and some of the hardest are used as
hearthstones, for example, in Hesse. Finally, since an edge is restored
to iron by water stones through a wearing away of each it follows that
whetstones are cooling and therefore when spread over the breasts of a
virgin or the testes of a young boy will stop their growth. Whetstone
is useful for the gout. Since an oil stone restores an edge to iron
because the iron is worn away it follows that the stone cleanses and,
for that reason, is used as an ointment to stop falling hair. The
Greeks call this disease alopecia.33
Gold and silver are tested on coticula (touchstone). The reason for this will be given in the book De Re Metallica. This stone is called βάσανος by
many Greeks, for example, Pindarus, Sophocles, Antiphon and Theog-nides
because the quality of the gold can be determined from its streak as
well as with a balance. For the same reason others have called the
stone χρνσΐτίς. Some call it lydius stone because it is found in Lydia; others heracleus stone
from the town of Heraclea in Lydia. All touchstone in the time of
Theophrastus was found in the Tmolus river, in the time of Pliny in a
number of places and today we get our touchstones from the rivers of
Hildesheim and Goslar and from the town of Visa between Egra and
Eredorf. Usually it is very dark with a characteristic smoothness.
Although Pliny writes that the largest is less than four inches long by
two inches wide it is found today six inches long and three inches wide
and even larger, especially near the village of Visa. Theophrastus
writes that experience has sho\vn that the stone which has been
partially exposed to the sun is the best while that which has lain in
water is inferior because it is not as dry as the former. Moisture
prevents the stone from taking the color of either gold or silver. A
good test cannot be made when the stone is hot for then the moisture
that is given off acts as a lubricant.
Pumex (pumice)
is found in localities that have been on fire at some time or are
burning now. It has been melted down from earth or stone and changed
into its present form. Typical pumice is found on Mt. Moderna and Mt.
Vesuvius in Campania; on the islands of Ischia and Aeoliae; in Sicily
near Aetna; on Melos and Nisida and on the sun-baked hills of
38 From the Greek άλώττηζ, a fox. Mange and loss of fur is very common among foxes.
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