The Wealth of Nations by Part 1 Chapter 8 Page 31

it varies a good deal less than in England. Such a difference of prices, which it seems is not always sufficient to transport a man from one parish to another, would necessarily occasion so great a transportation of the most bulky commodities, not only from one parish to another, but from one end of the kingdom, almost from one end of the world to the other, as would soon reduce them more nearly to a level.

After all that has been said of the levity and inconstancy of human nature, it appears evidently from experience that a man is of all sorts of luggage the most difficult to be transported. If the labouring poor, therefore, can maintain their families in those parts of the kingdom where the price of labour is lowest, they must be in affluence where it is highest.

Fourthly, the