labour should be more severe than the other, some allowance will naturally be made for this superior hardship; and the produce of one hour’s labour in the one way may frequently exchange for that of two hours’ labour in the other.

Or if the one species of labour requires an uncommon degree of dexterity and ingenuity, the esteem which men have for such talents will naturally give a value to their produce, superior to what would be due to the time employed about it. Such talents can seldom be acquired but in consequence of long application, and the superior value of their produce may frequently be no more than a reasonable compensation for the time and labour which must be spent in acquiring them.

In the advanced state of society, allowances of this kind, for superior hardship