Hammer's Patent: Safety Device for Electrical Circuits #397,715, February 12, 1889; #400,669
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 / 1.7: Patent Materials
unitdate: label: Date
content: April 2, 1889
container: label: Container
content: Box 21, Folder 8
dataSource: label: Archival Repository
content: Archives Center, National Museum of American History
objectType: label: Type
content: Archival materials