Daniel P. Woodbury 1812-1864 Union brigadier general who prepared the early defenses around Washington, fought at Bull Run, and constructed the famous road over the Chickahominy and White Oak Swamp Died of yellow fever. A.L.S. 1p. 4to., Springfield, Oh., Oct. 24, 1838 A very detailed letter describing magnetic variation in surveying instruments, and essentially apologizing for an incorrect survey.