346 THE BOOK OF THE PEARL'
kets,"
although they may also retain inferior pearls. A name used to indicate
the class of pearls found in the first four sieves is mel or mel-muttu, "upper" or "superior pearl," while vadivu designates those retained by the next three and tul those of the last three.
After
the pearls have been graded according to size and classified according
to quality, they are weighed. The unit of weight is themanchadi, the seed of Abrus precatorius, a small, red berry of practically uniform weight when ripe. H. W. Gillman of the Ceylon Civil Service reports the weight of the manchadi to be 3.35 grains troy. Fractional parts of a unit are obtained by using a berry called kundumani, grains of rice, etc., whose weights have been determined beforehand. A brass weight —the kalanchü—is also employed; it equals 67 grains or 20 manchadi.
However, choice pearls—those of the superior classes—are not valued in this manner, but at so much per chewu of their weight, which is three fourths of the square of the weight in manchadi. Thus, to find the value of an anatari pearl in the second sieve, if the weight be found to be three manchadi, three fourths of the square of three, or 6-3/4, is multiplied by the base value of the anatari class.
The
actual process of the calculation of value is as follows : owing to the
small size of the pearls, many fractions enter into the computations ;
to preserve uniformity it is customary to increase all fractions so
that each may have 320 as a denominator, this being a common multiple
of those that ordinarily arise in chewit calculations. The weight in manchadi of
the pearls is increased to a fractional figure having 320 as a
denominator. Three fourths of the square of the numerator of this
fraction is divided by the number of pearls, and this quotient is
divided twice consecutively by 320, giving the chewu of the weight. The market value then follows from the quoted price of the pearls per chewü at the time.
In
actual practice, these computations are not made ; but each merchant
provides himself with sets of tables showing the calculations for
different weights, analogous to the use of interest tables by bankers,
or of tables of logarithms by surveyors. Some of the merchants commit
these tables to memory, and at times may be heard reciting them quietly
to themselves to refresh the memory.
If
a pearl of a particular grade and class is of exceptional merit, the
merchant adds somewhat to the money value computed by the above
process. This applies especially to double pearls of the kürüval class, which sometimes consist of two fine bouton pearls suitable for setting, but not for stringing.
Pearls of one of the inferior or kalanchü classes are valued by simple weight, at so much per kalanchü, the market price, of course, differing for pearls of the various classes. The weight having been
