Radio tubes, World War I aircraft transmitter, excerpts from Hammer's notebook describing "phantom shadows" and a radio exhibit
name: label: Collection Creator
content: Hammer, William J. (William Joseph), 1858-1934 (electrical engineer)
setName: label: See more items in
content: William J. Hammer Collection
label: See more items in
content: William J. Hammer Collection / Series 4: Photographs / 4.3: Reference Materials
unitdate: label: Date
content: undated
container: label: Container
content: Box 110, Folder 3
dataSource: label: Archival Repository
content: Archives Center, National Museum of American History
objectType: label: Type
content: Archival materials
label: Type
content: Negatives