Labour was the first price, the original purchase - money that was paid for all things. It was not by gold or by silver, but by labour, that all wealth of the world was originally purchased.
Adam SmithGood roads, canals, and navigable rivers, by diminishing the expence of carriage, put the remote parts of the country more nearly upon a level with with those of the neighbourhood of the town. They are upon that the greatest of all improvements.
Adam Smith