the
use of sets of fractions arranged in a similar way. In this manner a
stock-book can be kept much more easily and with greater precision.
Others, again, have adopted a decimal notation of the fractions of a
carat, which is even more simple and feasible, since the common
fractions 1/2, 1/4, 1/8 etc. can be expressed as .5, .25, .125,
etc., of a carat, this being either a carat of .2053 of a gram or the
English carat of .20534 of a gram.
On
the other hand, an agreement was arrived at, as the result of a
conference between the diamond merchants of London, Paris, and
Amsterdam, by which the uniform weight of a diamond carat was fixed at
.205 of a gram, making the pearl grain .05125 of a gram. This standard,
which was suggested in 1871, by a syndicate of Parisian jewelers,
goldsmiths, and others dealing in precious stones, was subsequently
(1877) confirmed. But there is still a lack of uniformity in the
standard by which diamonds and pearls are bought and sold, and very
serious discrepancies exist in the sets of carat weights turned out by
different makers, although the international carat is almost
universally used.
At
the International Congress of Weights and Measures held at the World's
Fair at Chicago in 1893, the writer suggested that the carat should
consist of 200 milligrams, so that 1/2 of a carat would be 100
milligrams and 1/4 of a grain would be 12.5 milligrams. This would mean
5 carats or 20 grains to a French gram, and 5000 carats or 20,000 pearl
grains to a French kilogram. This would depreciate the present diamond
carat or pearl grain only about one per cent., and it would do away
with the needless series of carats and grains of the many
nationalities. It could be simply explained to any private individual
in any country, especially as there are only two countries which do not
use the metric system.
This
carat has been earnestly indorsed, its introduction advocated, and its
merits clearly shown, by M. Guilliame, of the French Bureau des Arts et
Métiers, whose energetic work has found a reasonable cooperation, in
this country as well as in Europe, in introducing what will be a
scientific, logical, comprehensive, and possibly the final and
international carat; and any ancient, obsolete, or foreign carat can
be readily reduced to this carat once the metric value of the former is
computed.
The
Association of Diamond Merchants of Amsterdam has already, to avoid
confusion, fixed the value of the carat (17th October, 1890) at 1
kilogram = 4875 carats, or 1 carat = 3.16561 grains troy = 205.128 mg.
One pearl grain = .7914 grains troy = 51.282 mg. ; but the association
has decided that, in case of litigation, these values shall be
determined by appointed bureaus, which would express them
