The Wealth of Nations by Part 4 Chapter 6 Page 25

melting down of the gold coin. If the seignorage had been two per cent there would have been neither profit nor loss. If the seignorage had been one per cent there would have been a profit, but of one per cent only instead of two per cent. Wherever money is received by tale, therefore, and not by weight, a seignorage is the most effectual preventative of the melting down of the coin, and, for the same reason, of its exportation.

It is the best and heaviest pieces that are commonly either melted down or exported; because it is upon such that the largest profits are made.

The law for encouragement of the coinage, by rendering it duty-free, was first enacted during the reign of Charles II for a limited time; and afterwards continued, by different prolongations, till 1769, when it was