Hank, the United States National Museum was the original museum
component of the Smithsonian Institution. You'll see the name on the
Arts and Industries Building. Basically, the A&I Building was the
original museum, and the "Smithsonian Institution" in the Castle
represented all the other non-museum activities of the Smithsonian.
After other museum buildings were constructed, they became part of the
U.S. National Museum. For a long time there was a single registrar for
the U.S. National Museum, even after the current National Museum of
American History ("Museum of History & Technology" carved in the stone,
under the blue banners) became a reality. When I started working for the
Smithsonian, the U.S. National Museum was composed of Natural History,
History and Technology, and Air and Space--but not the art museums. I'm
not sure when the National Museum title was retired and the museums got
individual registrars, but it's easy to find if you need it. --David
Haberstich