when used without adjunct, always means, in political economy, value in exchange.
Exchange value requires to be distinguished from Price. Writers have employed Price to express the value of a thing in relation to money—the quantity of money for which it will exchange. By the price of a thing, therefore, we shall [pg 250] henceforth understand its value in money; by the value, or exchange value of a thing, its general power of purchasing; the command which its possession gives over purchasable commodities in general. What is meant by command over commodities in general? The same thing exchanges for a greater quantity of some commodities, and for a very small quantity of others. A coat may exchange for less bread this year than last, if the harvest has been bad, but for more glass or iron, if a tax has been taken off those commodities, or an improvement made in their manufacture. Has the value of the coat, under these circumstances, fallen or risen? It is impossible