EDISON, THOMAS ALVA. Typed letter signed to an unidentified correspondent, New York, N.Y., 12 August 1886. 1 page, 4to, on personal letterhead. Boldly signed, with "umbrella" paraph. Edison announces an invention to improve the technology of telegraphy: "I have forwarded to you...a short description of my Phonoplex System of Telegraphy. This system will enable you to duplicate your way wire circuits and to add way circuits to your existing through wires, without any further investment in connection with line construction. With its assistance you can also introduce intermediate stations on duplex and quardruplex wires...I...feel confident that...you will recognize the value of the invention to your company..."