A map of the improved part of the Province of Pennsilvania in America : begun by Wil. Penn, Proprietary & Governour thereof anno 1681 /
Shows rural landholders' names, lot lines, and proprietary manors.
Map content (as of 1687) does not differ from earlier eds.
Title from upper border.
Statement of dedication at upper left:To the worthey William Penn Esq., Proprietor of Pennsilvania in America, this map is humbly dedicated by Iohn Thornton & Robert Greene.
Hand col. in pink watercolor to emphasize the map border; the map content is not colored.
Originally printed on 6 sheets assembled to form 1 large sheet; the large assembled sheet later was quartered and mounted on cloth backing.
LC copy imperfect: Upper left portion of map (including statement of dedication and coat-of-arms) torn away and replaced by photostat copy of the missing portion; annotated in lead pencil on cloth backing: Transferred from the Office of the Chief of Engineers, June 12, 1929.
Includes inset of "The city of Philadelphia" and Penn coat-of-arms.
Available also through the Library of Congress Web site as a raster image.
Ancient Maps from the Library of Congress. 13th -18th Century Maps.
In the 17th century, maps took a huge leap forward. Mathematical and astronomical knowledge necessary to make accurate measurements had evolved. English mathematicians had perfected triangulation: navigation and surveying by right-angled triangles. Triangulation allowed navigators to set accurate courses and produced accurate land surveys. Seamen learned to correct their compasses for declination and had determined the existence of annual compass variation. Latitude determination was greatly improved with the John Davis quadrant. The measurement of distance sailed at sea was improved by another English invention, the common log. Longitudinal distance between Europe and Québec was determined by solar and lunar eclipses by the Jesuit Bressani in the 1640s and by Jean Deshayes in 1686. With accurate surveys in Europe, the grid of the modern map began to take shape.