This folder contains correspondence from inventors and others asking for Edison's advice on technical matters or his assistance in improving or promoting inventions. Also included are general inquiries relating to the invention and patenting processes, along with letters requesting financial support for an invention or payments from Edison in exchange for providing him with ideas. The documents for 1919 cover a wide range of topics, including telephony, photography, electricity and magnetism, mining, transportation, health, and perpetual motion. Included are letters to and from Edwin A. Elsbach of the California Society for the Prevention of Blindness and Mrs. Winifred Hathaway of the National Committee for the Prevention of Blindness regarding Edison's renewed efforts to develop an ink for the blind and his doubts about the feasibility of using selenium cells as an alternative to braille. Also included are exchanges with J. J. Broderick on water power; with Walter Halfin on a plan to extract energy from the water-hydrogen cycle; with W. H. Kephart on manufacturing an ultraviolet ray machine; with U.S. Navy Lt. R. A. MacDonell on using gunpowder as fuel; and with Leavitt Mersereau of the E. W. Bliss Co. on timing torpedoes by sound.
Approximately 10 percent of the documents, including all letters bearing substantive marginalia by Edison, have been selected. Most of the unselected correspondence received a form-letter reply stating that Edison was too busy or that he did not become involved with others' inventions. A few items received informational replies from one of Edison's secretaries. Some of the letters bear routine Edison marginalia indicating that he did not remember the writer or that he had no special knowledge of the topic. Courtesy of Thomas Edison National Historical Park.