"There is not a Negro from the coast of Africa, who does not, in this respect, possess a degree of magnanimity, which the soul of his sordid master is too often scarce capable of conceiving.

Fortune never exerted more cruelly her empire over mankind, than when she subjected those nations of heroes to the refuse of the gaols of Europe, to wretches who possess the virtue neither of the countries they came from, nor of those they go to, and whose levity, brutality, and baseness so justly expose them to the contempt of the vanquished." And now, in 1770, in his Wealth of Nations, he showed in a forcible manner (for he appealed to the interest of those concerned) the dearness of African labour, or the impolicy of employing slaves.
Professor Millar, in his Origin of Ranks, followed Dr.Smith on the same ground.

He explained the impolicy of slavery in general, by its bad effects upon industry, population, and morals.

These effects he attached to the system of agriculture as followed in our islands.

He showed, besides, how little pains were taken, or how few contrivances were thought of, to ease the labourers there.