Smithsonian Astrophysical Observatory Radiation and Organisms Division Search this
Smithsonian Institution Building (Washington, D.C.) Search this
Century of Progress International Exposition (1933-1934 : Chicago, Ill.) Search this
4 x 3.25;
Between 1929 and 1934
See also MNH-11036F.
See also Record Unit 95, Box 31A, Folder 36.
Dr. Earl S. Johnston in the Division of Radiation and Organisms, located in the basement of the Smithsonian Institution Building, or Castle. Shown here is an apparatus for studying phototropism (bending toward light) of seedlings, in connection with experiments to determine effects of wave lengths of light on growth.