|Beginning with Robert Mill’s first design in
1841, a vast and unobstructed museum hall on the uppermost floor was a
desired characteristic of every plan for a Smithsonian building.
Although the second floor was designated as a museum in the 1849 plan,
when the building was completed in 1855, the second floor had been partitioned
into three chambers, housing an enormous lecture hall, an apparatus room,
and a gallery of art.
Until the fire of 1865, which destroyed the entire second floor, these rooms played an important and active role in the Smithsonian’s “diffusion of knowledge.” Only after the building was reconstructed was the hall turned over to museum use. Filled with specimens illustrating the history of human activity in the Americas, the grand second-story hall flourished as a museum for over forty years.