Signedunsigned
Inscribedwritten inside, four times: IX;
stamped on outside: 7-4 [obscured figure, possibly: 5]
FunctionConversion of sound into electrical signals for transmission over a distance
Historical AttributesOld tag: "Experimental electric transmitter old stamp #7-45 8005" Reverse: "With Telephon [sic] Collection from Jeff 1953"
ProvenanceJefferson Laboratory, Physics Department, Harvard University