Charles Mason

Charles Mason (April 1728 [baptised 1 May]25 October 1786) was an English astronomer who made significant contributions to 18th-century science and American history, particularly through his involvement with the survey of the Mason–Dixon line, which came to mark the border between Maryland and Pennsylvania (1764–1768). The border between Delaware and Maryland is also defined by a part of the Mason–Dixon line. Provided by Wikipedia