In1824-1828he was professor of mathematics and natural philosophy at Brown University, acting as president in 1826-1827; in1828-1831was president of Transylvania University, Lexington, Kentucky; and in1831-1837was president of the University of Alabama at Tuscaloosa, where he organized the Alabama Female Athenaeum.
He held the chair of Natural Philosophy in Marischal College, Aberdeen, from 1856 till the fusion of the two colleges there in 1860.
While he was still lecturing on natural philosophy at Queenwood College, his magnetic investigations made him known in the higher circles of the scientific world, and through the initiative of Sir E.
Though not so prominent as Huxley in detailed controversy over theological problems, he played an important part in educating the public mind in the attitude which the development of natural philosophy entailed towards dogma and religious authority.
In 1796 he lectured at Kiel, and a year later went to Jena to study the natural philosophy of Schelling.
But besides being a true educator, and perhaps the greatest popular teacher of natural philosophy in his generation, he was an earnest and original observer and explorer of nature.
Jean Pierre Minckelers, professor of natural philosophy in the university of Louvain, and later of chemistry and physics at Maestricht, made experiments on distilling gas from coal with the view of obtaining a permanent gas sufficiently light for filling balloons, and in 1785 experimentally lighted his lecture room with gas so obtained as a demonstration to his students, but no commercial application was made of the fact.
Boehme offers us a natural philosophy of the same sort.
In a word, Mach and Kirchhoff agree that force is not a cause, convert Newtonian reciprocal action into mere interdependency, and, in old terminology, reduce mechanics from a natural philosophy of causes to a natural history of mere facts.
A year later he was appointed professor of natural philosophy in Edinburgh University, in succession to Sir John Leslie and in competition with Sir David Brewster, and during his tenure of that office, which he did not give up till 1860, he not only proved himself an active and efficient teacher, but also did much to improve the internal conditions of the university.