The Wealth of Nations by Part 1 Chapter 5 Page 24

silver was at London exactly of the same value as at Canton. It is of no importance to him that half an ounce of silver at Canton would have given him the command of more labour and of a greater quantity of the necessaries and conveniences of life than an ounce can do at London. An ounce at London will always give him the command of double the quantity of all these which half an ounce could have done there, and this is precisely what he wants.

As it is the nominal or money price of goods, therefore, which finally determines the prudence or imprudence of all purchases and sales, and thereby regulates almost the whole business of common life in which price is concerned, we cannot wonder that it should have been so much more attended to than the real price.

In such a work as this, however,