The Wealth of Nations by Part 3 Chapter 2 Page 32

an inferior rank of people, even to the better sort of tradesmen and mechanics, and in all parts of Europe to the great merchants and master manufacturers. It can seldom happen, therefore, that a man of any considerable stock should quit the superior in order to place himself in an inferior station. Even in the present state of Europe, therefore, little stock is likely to go from any other profession to the improvement of land in the way of farming. More does perhaps in Great Britain than in any other country, though even there the great stocks which are, in some places, employed in farming have generally been acquired by farming, the trade, perhaps, in which of all others stock is commonly acquired most slowly.

After small proprietors, however, rich and great farmers are, in every country, the principal improvers.