A celebrated American institution "for the increase and diffusion of knowledge among men," in Washington; founded and endowed by James Macie Smithson, a natural son of the Duke of Northumberland, a zealous chemist and mineralogist, after having had a paper rejected by the Royal Society, of which he was a Fellow. The building is one of the finest in the capital; is under government control, and the President of the United States is ex officio the head of the institution; encourages scientific research, administers various funds, and directs expeditions for scientific purposes.