Nearly always when this has occurred the worn coins have still been accepted as money,[6] and ordinarily without any depreciation.

That is to say, they have a value as money greater than the value of the bullion that is in them.

Everybody takes them without hesitation as readily as if they were full weight.

If, however, at this point, new full-weight coins are put into circulation, these at once disappear while the old ones remain in circulation--a fact that has always been somewhat mystifying.
In explanation of the phenomenon was formulated "Gresham's law" of the circulation side by side of coins of different bullion value: bad money drives out good money.

Sir Thomas Gresham (whose name has but recently been given to this so-called law), explained the principle to Queen Elizabeth when counseling her regarding the recoinage of the debased money of the realm as was done in 1560.