Complex sentence: He taught chemistry and natural philosophy at Washington College (Lexington, Virginia), c1829-1830, and taught chemistry and natural history at Randolph-Macon College, 1833-1834, eventually being elected chair of the department.
Split into simpler sentences: He taught chemistry and natural philosophy at Washington College in Lexington, Virginia, from 1829 to 1830. He then taught chemistry and natural history at Randolph-Macon College from 1833 to 1834, eventually being elected chair of the department.