Slater, Robert. Telegraphic Code, To Ensure Secrecy in the Transmission of Telegrams, 1879.
name: label: Collection Creator
content: United Telegraph Workers.
label: Collection Creator
content: Western Union Telegraph Company
setName: label: See more items in
content: Western Union Telegraph Company Records
label: See more items in
content: Western Union Telegraph Company Records / Series 27: Addenda (Series Level) / Addenda for Miscellaneous
container: label: Container
content: Box 850
dataSource: label: Archival Repository
content: Archives Center, National Museum of American History
objectType: label: Type
content: Archival materials