DeWitt Clinton made his scientific researches constantly, even when executing mayor’s duties; scientific work was a creative escape for his life, dedicated to politics.
American intellectual life as intense as European was one of the main intentions of his cultural activity and the main idea of his longest lecture the Introductory discourse delivered before the Literary and Philosophical Society of New York (made in 1814).
In this lecture he considered the cases of European haughtiness to America, stated that America had the better climatic conditions and gave an explanation for the reasons of American inferiority in intellectual life.
The main reasons for distraction of intellectual activity were the darkness of the early settlement time, small population in a great country, and peculiarities of factional politics and political writings; also Clinton noted American progress in science and gave voice to concern about exhaustibility of natural resources.
He was interested in the history of Native Americans and archaeology. In 1812, he presented his lecture about the Iroquois to New York historical society. The statements of his lecture were the next: impossibility of concordance between people living by hunt and people living by agriculture, possibility to compare the Iroquois with the Romans. He criticized the theory about Indians as lost Tribes of Israel and sustained a theory of Asiatic origin and possible relations between Indians and the Scythian. He supposed that part of the Native Americans came from Northeast Asia by land. Other part could reach America by sea with regard to success of Phoenicians in sailing.
Speaking about scalping, he supposed that taking into account colonial wars, Indians were not responsible for that practice.
He believed that remains of ancient fortifications founded in America belonged to an ancient race, which settled these lands before Indians came from North Asia and after the period of resistance these ancient people disappeared.
Clinton’s vision of New York and America was full of imperial ambitions under the influence of history of ancient Rome, and nevertheless, he assumed the possibility of future recompense for the death of millions of Indians and slaves from Africa.
Apart from the history he wrote speeches, and addressed them to the students inspiring them to study hard. He created some works about zoology and Memoire of the Antiquities of the Western Parts of the State of New York. Pintard, Mitchill, and Hosack esteemed his contribution to science, and Clinton was elected as the member of learned society. But he did not avoid some unpleasantness such as critic of his introductory discourse by Gulian C. Verplank, or his fail when electing as honorable member of the Lyceum of Natural History in 1817. American Academy of the Arts had troubles inside, and some young members left it. The science became more professional. Though Clinton was an amateur, his contribution to the science was great enough for the politician.