Url https://edisondigital.rutgers.edu/document/PT005A Resource class dctype:Text Title [PT005A], Patent Application, Thomas Alva Edison, April 9th, 1873 Creator Edison, Thomas Alva Subject Multiple telegraphy (duplex, quadruplex) Publisher Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University Date 1873-04-09 Type Patent Application Identifier PT005A Source 8:549 Rights Thomas Edison National Historical Park Date Created 1873-04-09 Has Version https://archive.org/details/edisonmicrofilm8/page/n557/mode/1up Archive.org Viewer, Microfilm Series Reel 8 Is Part Of PT005A-F Uri https://edisondigital.rutgers.edu/document/PT005A https://edisondigital.rutgers.edu/document/PT005A --