died on this date in 1829.
Smithson’s will left the bulk of his estate to his nephew, Henry James Hungerford. But should his nephew die without children—legitimate or illegitimate—a contingency clause stated that the estate would go to “the United States of America, to found at Washington, under the name of the Smithsonian Institution, an Establishment for the increase and diffusion of knowledge…”
Source: The Smithsonian Institution
The nephew did indeed die without children and in 1838 approximately $500,000 in gold was brought to the United States. After a decade of indecision and debate about how best to carry out the bequest, the Smithsonian Institution was created by Act of Congress (1846).
An aside: According to the Smithsonian:
Senator John C. Calhoun opposed acceptance of the Smithson bequest, largely on the grounds that to do so on behalf of the entire nation would abridge states’ rights. He maintained that Congress had no authority to accept the gift. He also asserted that it would be “beneath [U.S.] dignity to accept presents from anyone.”