He was an assistant professor for 12 years at the University of Pennsylvania.
His job at Smithsonian was to organize meteorological reports, and arranging of scientific lectures, under a supervision by secretary Joseph Henry.
While being employed at the Smithsonian, he also served as professor of chemistry in the National Medical College.
He got a job of chief examiner in the Patent office in 1852, a position he kept till 1860.
In 1874, he came back to Smithsonian as a collaborator in ethnology from the United States National Museum.