US Patent 1,816,465, Cardiotachometer
name: label: Collection Creator
content: Boas, Ernst P. (Ernst Philip), 1891-1955
setName: label: See more items in
content: Ernst P. Boas Papers
label: See more items in
content: Ernst P. Boas Papers / Series 1: Cardiotachometer Materials / 1.1: Correspondence
unitdate: label: Date
content: 1931 July 28
container: label: Container
content: Box 1, Folder 1
dataSource: label: Archival Repository
content: Archives Center, National Museum of American History
objectType: label: Type
content: Archival materials