The Wealth of Nations by Part 1 Chapter 5 Page 23

goods from the one to the other has nothing to consider but their money price, or the difference between the quantity of silver for which he buys them, and that for which he is likely to sell them. Half an ounce of silver at Canton in China may command a greater quantity both of labour and of the necessaries and conveniences of life than an ounce at London. A commodity, therefore, which sells for half an ounce of silver at Canton may there be really dearer, of more real importance to the man who possesses it there, than a commodity which sells for an ounce at London is to the man who possesses it at London.

If a London merchant, however, can buy at Canton for half an ounce of silver, a commodity which he can afterwards sell at London for an ounce, he gains a hundred per cent by the bargain, just as much as if an ounce of