Of the 70 per cent 50 was gold, 18 was silver, and 2 was copper and nickel.] Sec.4.

#Light-weight fractional coins.# The standard metal is usually too valuable to be suitable for coins of the smaller denominations.
Therefore, when gold is the standard, copper, nickel, and silver remain in restricted use.

But when coins of these metals are issued at weights corresponding with their bullion value, difficulties arise.
Not only are they too heavy for convenience, but with every slight rise in their bullion value as compared with that of the standard metal, they become worth more as bullion than as coin and begin to disappear from circulation.

This happened often throughout the Middle Ages and until the nineteenth century.

The attempt was generally made to coin gold and silver at a ratio of weight corresponding exactly to their market values at a given moment and, every time the market conditions varied, the best full-weight coins of one of the two metals were taken out of circulation.