United States. Patent Office · Washington, D.C., Govt. Print. Off. · leaf 749
ing material. 5. As a new article of maiuifacture, a dia- 85phragm, for talking-machines, consisting of a perforated metallic disk having bossesthereon surrounding the perforations there-in at one end of each, hardened filling mate-rial in the perforations in said disk, and 90hardened coating… … M(/.<3.
Phonograph · Patents
Internet Archive · Smithsonian Libraries · Public Domain Mark 1.0. Free to use for anything.
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