Another word for coal miner in Scotland is collier. Tom Caldwell's Scottish ancestors shared a life of virtual slavery. In 1601 an Act was passed binding colliers to perpetual service at the works at which they were engaged, and their full emancipation did not take place till 1799. (Encyclopedia Britannica, 9th edition, 1892, Vol. XXI, Scotland, p. 532; see generally, Hair, P.E.H. 'Slavery and Liberty: The Case of the Scottish Colliers,' SLAVERY AND ABOLITION. (21:3), December 2000, pp. 136-151.)