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