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184
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DE NATURA FOSSILIUM
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the
sky, accompanied by a fiery hissing thus giving warning in two ways.
There is a goblet of this type in the temple to Minerva in Lindos, a
town of Rhodes. Homer writes that Menelaus wore a ring made of electrum.
The finest mirrors are made from stannum.
In
this same fashion, Nature sometimes mixes three metals, for example,
gold, silver and copper, and at other times four, silver, copper, tin
and bismuth. Having been instructed by Nature we also mix metals in
this fashion. Not only does Nature teach us the correct proportions to
use in the alloys but we also learn through accidents to imitate
Nature. For example, in a fire at Corinth gold, silver and copper were
melted together and by good fortune combined in the correct proportions
of the three varieties of Corinthian copper. One of these is white and,
as Pliny writes, approaches closest to the appearance of silver when
that metal is the dominant one. Another is as yellow as gold. The
third has the three metals in equal proportions. Art and fraud imitate
Nature through mixing metal with metal in various proportions. The
Greeks call this correct proportioning κράματος, the Romans temperatura. Two,
three, or more, simple or complex metals may be mixed together. A
simple metal may be mixed with a complex, a complex with a simple, two
simple with one complex, two complex with one simple, and many simple
with one or two complex metals and vice versa. The proper proportion of
these metals varies since sometimes a base metal is mixed with a
precious metal and vice versa. One should examine every alloy to
determine whether it may be of any use at present or at some future
time. It may have neither a present nor future use or it may have a
future use and be of no present value or it may have a present use and
be of no use in the future. Next one should consider what use each may
or may not have. It should be examined to determine if it is a
fraudulent or artificial alloy. Finally one should determine what name
the Greek or Roman writers have given it or if it lacks a name.
First
we shall consider gold that is mixed in various proportions. All these
alloys lack names except that with one part of silver to four parts of
gold which we call electrum. Certain men make a practice of
mixing a small quantity of some base metal with a large mass of
precious metal, not to make a legitimate alloy but to make a profit.
They admit this to be a crime since they do their work in secret.
Mention could be made of the fraudulent contractor to whom Hiero of
Syracuse gave a contract to make a crown. As he made the crown he
substituted silver for some of the gold. This theft was finally
detected by Archimedes. On the other hand kings and princes protect the
worker who substitutes silver for gold in making coins since they say
they have the legal right to make money that is not pure gold. Flavius
Vopiscus writes that the Emperor Tacitus, in a speech before the
senate, ordered that it be considered a capital crime for anyone to
mix copper with silver, silver with gold, or lead with silver, either
publicly or privately and offer it for sale as pure metal. This just
and good
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