ht. (The old carat was approximately .205
g., while the new one is .200 g. Hence one old carat

.205 .102-1/2
is ---- = -------- = 102-1/2% of a new one.)
.200 .100

METHOD OF CONVERTING WEIGHTS. If the old weight has fractions these
should first be changed to decimals for convenience. For example,
suppose it is wished to change 2-1/4 1/16 old carats to metric carats.
1/4 = .25 and 1/16 = .0625. Hence 2-1/4 1/16 = 2.3125. Now get 102-1/2%
of this: (2.3125 x 1.025 = 2.37 metric carats).

If, for any reason one should need to change from metric carats to old
U. S. carats one should multiply by .9756

( .200 g. )
( ------- = .9756 )
( .205 g. )

As was said in Lesson XXV., pearls are sold by the _pearl grain_, which
is arbitrarily fixed at 1/4 of a carat. With the change to the metric
carat the pearl grain was correspondingly changed and its weight is now
1/4 of .200 g. = .05 g., as expressed in the metric system.

LESSON XXX

TARIFF LAWS ON PRECIOUS AND IMITATION STONES

Since it is necessary for a nation, as well as for an individual, to
have an income, and since articles of luxury are more easily taxed than
are those of necessity, the traffic in gems and their imitations has
frequently been made a source of revenue to our government. Usually the
per cent. charged as tariff has been comparatively low, especially upon
very valuable gems, such as diamonds and pearls, for the reason that too
high a tariff would tend to tempt unscrupulous dealers to smuggle such
goods into the country without declaring them. When the margin of
difference between the values, with and without the tariff, is kept
small the temptation is but slight, when the danger of detection and
the drastic nature of the usual punishment are taken into account. Rough
stones have frequently been allowed to enter the country duty free
because they were regarded as desirable raw materials which would afford
employment to home industry.

The tariff laws of October 3, 1913, made, however, some sweeping changes
in the policy of our government toward precious stones and as those laws
are still in force (April 4, 1917) this lesson will attempt to set forth
clearly the exact conditions under the present law.

Perhaps the paragraph of first importance to the trade is No. 357 which
reads as follows.

"357. Diamonds and other precious stones, rough or uncut, and not
advanced in condition or value