purchased by his master John Wedderburn in Jamaica and brought to Scotland, left him. Married and with a child, he filed a freedom suit, on the grounds that he could not be held as a slave in Great Britain. In the case of Knight v. Wedderburn (1778), Wedderburn said that Knight owed him "perpetual servitude". The Court of Session of Scotland ruled against him, saying that chattel slavery was not recognized under the law of Scotland, and slaves could seek court protection to leave a master or avoid being forcibly removed from Scotland to be returned to slavery in the colonies. But at the same time, legally mandated, hereditary slavery of Scots persons in Scotland had existed from 1606 and continued until 1799, when colliers and salters were emancipated by an act of the Parliament of Great Britain (39 Geo.III. c. 56). Skilled workers, they were restricted to a place and could be sold with the works. A prior law enacted in 1775 (15 Geo. III. c. 28) was intended to end what the act referred to as "a state of slavery and bondage," but that was ineffective, necessitating the 1799 act. In the 1776 book The Wealth of Nations, Adam Smith argued for the abolition of slavery on economic grounds. Smith pointed out that slavery incurred security, housing, and food costs that the use of free labour would not, and opined that free workers would be more productive because they would have personal economic incentives to work harder. The death rate (and thus repurchase cost) of slaves was also high, and people are less productive when not allowed to choose the type of work they prefer, are illiterate, and are forced to live and work in miserable and unhealthy conditions. The free labour markets and international free trade that Smith preferred would also result in different prices and allocations that Smith believed would be more efficient and productive for consumers. British Empire Prior to the American Revolution, there were few significant initiatives in the American colonies that led to the abolitionist movement. Some Quakers were active. Benjamin Kent was the lawyer who took on most of the cases of slaves suing their masters for personal illegal enslavement. He was the first lawyer to successfully establish a slave's freedom. In addition, Brigadier General Samuel Birch created the Book of Negroes, to establish which slaves were free after the war. In