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 Xo.
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. IS
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 direction for
the preparation of a chemical salt. Many vegetable dyes and other
organic substances were employed in dyeing the treated crystal, among
which were alkanet, celandine, cedar oil, pitch, and various resins. In
some cases the two operations were combined in one. It is to be
remarked that many of the recipes carry various detailed precautions
concerning the processes, showing the presence of much experience in
carrying them out. We may well question the beauty and the permanency
of the imitation gems prepared by these methods, but probably they
satisfied the people of that period. These methods of imitating
precious stones 'seem
