Rare First Issue of the Mason-Dixon Survey

"A Map of That Part of America Where a Degree of Latitude Was Measured for the Royal Society by Cha: Mason & Jere: Dixon", Mynde, James

This interesting little map covers the Delaware peninsula north to Philadelphia with only a few cities and roads including Annapolis, Baltimore, and Greenwich. It locates many early settlements and shows the roads that connect them. The focus of the map is the initial measurements made by Charles Mason & Jeremiah Dixon for what has become known as the Mason-Dixon Line. These two British astronomers were employed to make this survey in order to resolve a long-standing dispute between the Calvert family, proprietors of Maryland, and the Penn family of Pennsylvania. This map, one of the first to show the results of the Mason Dixon survey, shows this initial degree of latitude set into the context of the lands around the Chesapeake and Delaware Bays. This edition appeared in The Philosophical Transactions of the Royal Society of London, reflecting the general public interest in this border dispute in the American colonies. A later edition of this map was published the following year in the December 1769 issue of the Gentleman's Magazine. Included with the map are 59 loose pages of text from the publication (pp. 270-328) explaining how Mason and Dixon saw an opportunity to determine a degree of latitude while conducting the survey of the Maryland -Pennsylvania line.

References: cf. Jolly #GENT-199.

Condition: B+

The map is issued folding with light toning and two tiny edge tears confined to the blank margin closed on verso with archival material. Loose text is clean with light toning.