The Wealth of Nations by Part 5 Chapter 2 Page 21

what would be necessary for seed. The population of the country would be less by the number of people which thirty millions a year, deducting always the seed, could maintain according to the particular mode of living and expense which might take place in the different ranks of men among whom the remainder was distributed.

Though there is not at present, in Europe, any civilised state of any kind which derives the greater part of its public revenue from the rent of lands which are the property of the state, yet in all the great monarchies of Europe there are still many large tracts of land which belong to the crown. They are generally forest; and sometimes forest where, after travelling several miles, you will scarce find a single tree; a mere waste and loss of country in respect both of produce and population.