London: Mount & Davidson, Tower-Hill, 1794. unbound. Map. Uncolored engraving. Image measures 22.75" x 19.5", page including text measures 26.5" x 27 7/8" very good(+).
Beautiful and rare chart of the Atlantic including South America and parts of North America, Europe and Africa. Features lines of magnetic variation, or how much the compass deviates from true north. As explained in the two columns of pasted text, these observations are based upon the work of Dr. Edmond Halley in 1700 with additions in 1744. Other elements include two compass roses, extensive place names, and a note and depiction of fabled sea birds off the eastern coast of South America. The map was originally published by William Mount, John Mount and Thomas Page in "The English Pilot. The Fourth Book" circa 1750. This edition was reissued by William Mount II and James Davidson. Light offsetting. Expert repair to split along original centerfold. The "English Pilot" was a sea-chart atlas published in several editions from 1671 to 1803. The Mount family was active in publishing in various manifestations for many generations from the 1650s to 1800.