[The first paragraph of this note covers all of the Unbound Notes and Drawings for Part I.]
The loose technical notes and drawings constituting this collection cover the years 1873-1878. They relate to a variety of subjects, including telegraphy, electric lighting and power, the electric pen and duplicating press, the telephone, and the phonograph. There are also documents pertaining to various other subjects, such as carbon rheostats, acoustic devices, the tasimeter, and the voltameter. The unbound notes and drawings are organized by year and within each year by subject. Undated notes and drawings, organized by subject, follow the dated material.
This folder contains 11 pages of notes, drawings, and patent tracings relating to the cylinder phonograph. Included are two notes from Charles Batchelor to John Kruesi, the machinist who constructed the first tinfoil phonograph in December 1877. Courtesy of Thomas Edison National Historical Park.