[D9211AHX], Letter from Thomas Alva Edison to Egisto Paolo Fabbri, November 9th, 1892
https://edisondigital.rutgers.edu/document/D9211AHX
Transcription
Nov. 9, 1892. My dear Fabbri,- Your letter of 21st instant is received. I regret that the material for the phonograph did not reach you properly. Regarding the cylinder with record of my voice, put the tubes in your ears, and adjust the regulating governor to such a speed that you will recognize the voice. A faithful reproduction cannot be obtained on the phonograph unless the cylinder is made to revolve at the exact speed. Yours very truly, E. P. Fabbri, Esq., Florence, Italy.