The
reports, too, are at least as often made as ounces in the short ton of
2000 lbs., as on the more orthodox ton of 2240 lbs. Now the short ton is
equal to 29,166.6 troy ounces; and the corresponding "assay ton" is got
from it by replacing ounces by milligrams. The advantage of its use is
that if one assay ton of ore has been taken, the number of milligrams of
gold obtained is also the number of ounces of gold in a ton of the ore,
and there is absolutely no calculation. Even if half an assay ton has
been taken the only calculation needed is multiplying the milligrams by
two. On the other hand with a charge of two assay tons the milligrams
need halving. Where weights of this kind (_i.e._, assay tons) are not at
hand they may be easily extemporised out of buttons of tin or some
suitable metal, and it is better to do this than to array out the grams
and its fractions at each weighing. The sets of "assay tons," however,
are easily purchased. As stated on page 13, the assay ton for 2240 lbs.
is 32.6667 grams; and for the short ton, 29.1667 grams. If, however, the
round number of grams be used and the result brought by calculation to
the produce on 100 grams, the conversion to ounces to the ton may be
quickly effected by the help of the table on page 107. As this table
only deals with the ton of 2240 lbs.
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