The Leyden and Stockholm Papyri - University of Cincinnati

THE LEYDEN & STOCKHOLM PAPYRI
mixture, then to peel this off again. This latter operation apparently
removed the objectionable dirt. Recipe No. 61, in which lime is
employed in this manner, apparently contains some rudimentary
attempt at chemical theory. Various liquids were also employed in
cleaning. Perhaps the most curious and the least scientific of these
cleaning methods is that described in Recipes No. 25 and 60 in
which the pearl is given to a fowl to eat and is afterward recovered
and found to be cleaned. This set of recipes contains the first
account of the manufacture of imitation pearls. Recipe No. 18
describes their preparation in which shimmering scales from mica
or ground selenite were incorporated in a paste made from gum,
wax, mercury, and white of eggs. This was then shaped and dried,
probably yielding an inferior imitation of the real thing, although
the last sentence of the recipe assures us otherwise. Recipes No. 22
and 23 detail other methods of accomplishing the same end.
! The remainder of the recipes of the second group deal with the
imitating of emerald, ruby, beryl, amethyst, sunstone, and other
valuable gem stones. The base for nearly all of these imitations is
the so-called crystal. This word in Greek is generally understood to
mean quartz or rock crystal. Probably, however, its meaning in the
papyrus was extended to other clear stones, notably to selenite,
since the processes used depended somewhat upon having more
easily corroded stones than quartz. At any rate, the first step in the
manufacture of imitation precious stones, as practiced in ancient
Egypt, was to treat the base used in such a way as to roughen it and
to make the surface of the stones porous. Various substances and
methods were used for this purpose. The heated stones were generally
boiled or dipped in oil, wax, or solutions of alum, native soda,
common salt, vinegar, calcium sulfide, or in mixtures of these. By
this means the surface of the stone used was roughened and also,
probably to some degree, mordanted for the application of dyes.
After corroding or mordanting the stone in this manner some kind
of a dyeing material was then applied. These latter fall into two
classes, the inorganic and the organic substances. Copper salts, for
example, were usually applied to form imitation emeralds from the
base, while alkanet was used for red stones. Recipe No. 74 is of
special interest in that it gives the method of preparing verdigris
for this very purpose. This is probably the first detailed laboratory
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