Meet Mason and Dixon, Who Spent 5 Years Plotting Line

"It was the equivalent of the moon landings today," according to Mason-Dixon Line expert David Thaler.

Baker's son Charles Mason and lapsed Quaker Jeremiah Dixon were established scientists when commissioned to settle a land dispute in the pre-revolutionary America of 1763.

For 80 years the Calvert family of Maryland and the Penns of Pennsylvania had been locked in a bloody dispute over the boundary between the two colonies they had been granted by the English Crown.

"The stakes were very high," said Mr Thaler, trustee of the Maryland Historical Society in Baltimore and an expert on the Mason-Dixon project.