The Wealth of Nations by Part 5 Chapter 2 Page 50

To draw the attention of the sovereign towards the improvement of the land, from a regard to the increase of his own revenue, is one of the principal advantages proposed by this species of land-tax. The term, therefore, allowed for the indemnification of the landlord ought not to be a great deal longer than what was necessary for that purpose, lest the remoteness of the interest should discourage too much this attention. It had better, however, be somewhat too long than in any respect too short. No incitement to the attention of the sovereign can ever counterbalance the smallest discouragement to that of the landlord. The attention of the sovereign can be at best but a very general and vague consideration of what is likely to contribute to the better cultivation of the greater part of his dominions.

The attention of the