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.

If I discover a manure which will enable me to make a piece of land produce 20 per cent more corn, I may withdraw at least a portion of my capital from the most unproductive part of my farm.

The factors left out of the Ricardian equation are falling wages and idle capacity.

It is here we come to the heart of the matter. The economic principle of comparative advantage', 'a country may, in return for manufactured commodities, import corn even if it can be grown with less labour than in the country from which it is imported

Utility then is not the measure of exchangeable value, although it is absolutely essential to it.

There can be no greater error then in supposing that capital is increased by non-consumption.

Gold, on the contrary, though of little use compared with air or water, will exchange for a great quantity of other goods.