pp. 217-25 all appear to be drawings related to deaf appartus see N314241 from same date

Edison, Thomas Alva

1886-03-28

1880-1889

Technical Note

Microphone and other acoustic devices

N314217

N314

[N314217] Technical Note, March 28th, 1886

42:921

Thomas Edison National Historical Park

Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University