ine-tenths fine; in Great Britain,
eleven-twelfths. The established weight of the gold dollar in the
United States is 25.8 grains of standard gold which contain 23.22
grains of fine gold. The _limit of tolerance_ is the variation either
above or below the standard weight or fineness that a coin is allowed
to have when it leaves the mint. This is different for each of the
principal coins, being about one-fifth of one per cent on a gold
eagle. The _par of exchange_ between standard coins of different
countries is the expression of the ratio of fine metal in them.
Thus the par of exchange between the American dollar and the English
sovereign (the "pound") is 4.866; that is, that number of dollars
contains the same amount of fine gold as an English gold sovereign.
The embossed design is merely to make the coins easily recognizable
and difficult to counterfeit; and milled or lettered edges are to
prevent clipping and otherwise abstracting metal from the coins.

10. #Seigniorage defined#. Coinage, as practised by early governments
and rulers, came to be a function of great importance politically as
well as economically. The right to issue money came to be one of
the most essential prerogatives of sovereignty. The prince, king, or
emperor stamped his own device or portrait upon the coin; hence the
term seigniorage from _seignior_ (meaning lord or ruler). Seigniorage
meant primarily the right the ruler, or the estate, has to charge
for coinage, and hence it has come to mean also the charge made for
coinage, and often, in a still broader sense, the profit made by the
government in issuing any kind of money with a value higher than that
of the materials (whether metal or paper) composing it. Coinage is
rarely without charge, and often has been a source of revenue to the
ruler. In antiquity and in the Middle Ages this right was frequently
exercised by princes for their selfish advantage to the injury and
unsettling of trade. This introduced a very great problem of value
into the use of money.

The coinage is said to be _gratuitous_ when no charge is made for
coinage. Coinage is said to be _free_ if the subject or citizen
may take bullion to the mint whenever he pleases, paying the
usual seigniorage. Coinage is _limited_ if the government or ruler
determines when coinage is to take place. Thus, coinage may be both
free and gratuitous, when citizens are allowed to bring bullion
whenever they please and have it converted into coins