"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."

“Adam Smith, and other able writers to whom I have alluded, not having viewed correctly the principles of rent, have, it appears to me, overlooked many important truths, which can only be discovered after the subject of rent is thoroughly understood.”

“It has been my endeavour to show in this work that a fall of wages would have no other effect than to raise profits.”

“Whenever the current of money is forcibly stopped, and when money is prevented from settling at its just level, there are no limits to the possible variations of the exchange.”

“No extension of foreign trade will immediately increase the amount of value in a country, although it will very powerfully contribute to increase the mass of commodities and therefore the sum of enjoyments.”

“If a tax on malt would raise the price of beer, a tax on bread must raise the price of bread.”

“But it is clear that the price of labour has no necessary connection with the price of food, since it depends entirely on the supply of labourers compared with the demand.”