Records and Results of a Magnetic Survey of Pennsylvania and parts of adjacent States in 1840 and 1841, with some additional Records and Results of 1834, 1835, 1843, and 1862, and a mapSmithsonian Institution82
Bache, Alexander Dallas. 1863. Records and Results of a Magnetic Survey of Pennsylvania and parts of adjacent States in 1840 and 1841, with some additional Records and Results of 1834, 1835, 1843, and 1862, and a map. Washington, D.C.: Smithsonian Institution. In Smithsonian Contributions to Knowledge, 166.