The Wealth of Nations by Part 2 Chapter 5 Page 11

It augments the value of those materials by their wages, and by their matters’ profits upon the whole stock of wages, materials, and instruments of trade employed in the business.

It puts immediately into motion, therefore, a much greater quantity of productive labour, and adds a much greater value to the annual produce of the land and labour of the society than an equal capital in the hands of any wholesale merchant.

No equal capital puts into motion a greater quantity of productive labour than that of the farmer. Not only his labouring servants, but his labouring cattle, are productive labourers. In agriculture, too, nature labours along with man; and though her labour costs no expense, its produce has its value, as well as that of the most expensive workmen. The most important