To George Washington president of the United States of America this magnetic atlas or variation chart is humbly inscribed by John Churchman.

• Format: Map
• Language: unknown
• Published: Philadelphia: James Johnson: 1790 1790
• Subjects: Maps; Magnetic Atlas; North Pole; South Pole; The Needle; South pole
• Online Access: https://diglib.amphilsoc.org/islandora/object/george-washington-president-united-states-america-magnetic-atlas-or-variation-chart

In: Pam. 538.7:C47e. John Churchman, An explanation of the magnetic atlas or variation chart. Philadelphia: James Johnson: 1790. Front. Churchman was an American who was devoted to his own theories of the variations of the magnetic needle and other things. He had presented his scheme to the Society...