[D0104AAL], Letter from Thomas Alva Edison to Willis N Stewart, July 15th, 1901
https://edisondigital.rutgers.edu/document/D0104AAL
Transcription
My Dear Steward I was surprised to learn that you had bought Junger's patents, you will find that, they have no value, because they are based on theory. + actual experiment will prove his patents bad in every particular. Edison