Title: Correspondence
Subjects: Correspondence, National Academy of Sciences (U.S.), Geomagnetism, United States Coast Survey, Magnetic declination, Observations, United States and Mexican Boundary Survey
Places: United States, Mexico
People: J. E. Hilgard (1825-1891), George Engelmann (1809-1884), Henry Wilson (1812-1875), Joseph Henry (1797-1878), Louis Agassiz (1807-1873), A. D. Bache (1806-1867)