The Wealth of Nations by Part 5 Chapter 2 Page 78

kind might, according to those different circumstances, affect very unequally both the inhabitant of the house and the owner of the ground.

The inequality with which a tax of this kind might fall upon the owners of different ground-rents would arise altogether from the accidental inequality of this division.

But the inequality with which it might fall upon the inhabitants of different houses would arise not only from this, but from another cause. The proportion of the expense of house-rent to the whole expense of living is different in the different degrees of fortune. It is perhaps highest in the highest degree, and it diminishes gradually through the inferior degrees, so as in general to be lowest in the lowest degree. The necessaries of life occasion the great expense of the poor.