Labour began to be important to national prosperity as more people left the agricultural community and migrated to the cities to work in the new factories that developed during the industrial revolution. It was here that wages, or a person’s time, were included as a accost factor in determining prices. However, despite this innovative consideration, most mercantilists felt that it was even more important that wages be kept to a minimum since too much money would lead to higher birth rates, which in turn, with more people seeking employment, would cause wages to fall perhaps even to below subsistence levels and thus cause untold human suffering, In this fashion, according to economists of the day, the worker was saved from himself and paid only what was necessary to live on. It was in this context that Karl Marx, seeing the abject misery of workers in the steam-driven sweatshops of England, concocted his version of labour as a source of value directly, or as it was contained in tools or machines and plants.