[ Autographs ] HEINRICH HERTZ (1857 - 1894) German physicist who demonstrated the existence of electromagnetic waves, showed they could be refracted and reflected, his discoveries led to the development of wireless telegraphy. Rare good content A.L.S. 2pp. 8vo. Bonn, Mar. 10, 1892 to a colleague, in German. In part: "....For yourfriendly words on my overall theory I offer my best thanks...your central questions are these: whether you can get your fine work submitted to a publisher, and whether the central points of my ideas were adequately and correctly expressed. These questions I can answer in the affirmative...It is not yet illegal and common custom is well established that literary theft in the proper spirit is not the same as common theft. The dignity of a manuscript my be preserved against fire or loss, but not against indiscreet usage...". Folds, otherwise fine condition.