[PT031AAH], Patent Caveat, Thomas Alva Edison, December 9th, 1889
Filed caveat (draft is Nov. 2, 1889) oath is December 8, 1889
[PT031AAH-F] Patent Series -- Caveat Files
https://edisondigital.rutgers.edu/document/PT031AAH
Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
Archive.org Viewer, Microfilm Series Reel 113