In stating the principles which regulate exchangeable value and price, we should carefully distinguish between those variations which belong to the commodity itself, and those which are occasioned by a variation in the medium in which value is estimated, or price expressed.

It is not by the absolute quantity of produce obtained by either class, that we can correctly judge of the rate of profit, rent, and wages, but by the quantity of labour required to obtain that produce.

In the same manner if any nation wasted part of its wealth, or lost part of its trade, it could not retain the same quantity of circulating medium which it before possessed.

David Ricardo Quotes