Among foreign systems of weights, the French is by far the best.
Kilograms (2.205 lbs.) per quintal (220.5 lbs.) are parts per cent.; and
grams (15.43 grs.) per quintal are parts per 100,000. From the rule
already given, grams per quintal may be converted into ounces to the ton
by multiplying by 0.327.

The German loths per centner (1/2 oz. (avoirdupois) to 100 lbs.) equal
parts per 3200; they are converted into parts per cent. by dividing by
32, or into ounces (troy) per ton by multiplying by 10.208.

In the United States, as a sort of compromise between the avoirdupois
and metric systems, a ton is taken as 2000 lbs. There, too, the custom
is adopted of reporting the gold and silver contents of an ore as so
many dollars and cents to the ton. In the case of gold, an ounce is
considered to be worth 20.6718 dollars. With silver, the _nominal_ value
is 1.2929 dollars per ounce, but frequently in assay reports it is taken
as one dollar. The practice is objectionable. The prices of metals vary
with the fluctuations of the market, and if the assayer fixed the price,
the _date_ of his report would be all important; if, on the other hand,
he takes a fixed price which does not at all times agree with the market
one, it leaves a path open for the deception of those unacquainted with
the custom. American "dollars on the ton of 2000 lbs." may be converted
into "ounces in the ton of 2240 lbs." by dividing by 1.1544 in the case
of silver, and by 18.457 in the case of gold.

~Laboratory Books and Report Forms.~--The record which the assayer makes
of his work must be clear and neat, so that reference, even after an
interval of years, should be certain and easy. One method should be
adopted and adhered to. Where there are a large number of samples, three