The common wages of labour depends every where upon the contract usually made between those two parties whose interests are by no means the same†Masters are always and every where in a sort of tacit, but constant and uniform combination, not to raise the wages of labour above their actual rate.

-Smith, Adam
  An Inquiry into the Nature and Causes of theWealth of Nations, bk.1, ch.8.

The rate of profit does not, like rent and wages, rise with the prosperity, and fall with the declension, of the society.On the contrary, it is naturally low in rich, and high in poor countries, and it is always highest in the countries which are going fastest to ruin.

-Smith, Adam
  An Inquiry into the Nature and Causes of theWealth of Nations, bk.1, ch.11, conclusion.