Automatic boiler feed by selenium cell control of the pump
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 1: William J. Hammer Papers / 1.4: Writings by Hammer / Diagrams, Drawings, Sketches, and Graphs:
unitdate: label: Date
content: 1910
container: label: Container
content: Box 17, Folder 3
dataSource: label: Archival Repository
content: Archives Center, National Museum of American History
objectType: label: Type
content: Archival materials