“An unnamed European visitor, in dialogue with Jefferson, as quoted in A Winter in Washington : or, Memoirs of the Seymour Family (1824) by Margaret Bayard Smith, Vol. 2, p. 37; a few years later Sketches of the Life, Writings, and Opinions of Thomas Jefferson (1832) by B. L. Rayner presents a slightly different rendition of this dialogue, and identifies the visitor as Baron Alexander von Humboldt, who visited Washington in June 1804:”

Source: Wikiquote