Part Of: Notebook Series -- Notebooks by Other Experimenters -- Phonograph Record Experiments -- Disc Plating Books

[NB209-F] N-13-09-27 (1913-1914)

This notebook was used by William Walter Dinwiddie during September 1913-August 1914. One additional notation was probably made in February 1915. The book begins with the inscription, "Let no one see this book without very definite orders from Mr. Edison." The entries consist primarily of a series of formulas, along with instructions describing current practices for plating the masters and submasters used in making Edison disc records. These were probably the culmination of numerous plating experiments documented in earlier books in this subgroup. Additional experimentation produced modifications in formulas and practices. For example, the use of submasters was discontinued shortly after 1913. Some of the formulas have been crossed out and changed, with an indication of the date on which the practice changed.

Among the practices described in this notebook is the method of preparing "dopes" (caminol and copper ink) for use in plating the wax masters, along with an indication of the object of using each dope. Also included is a description of the method of purifying the graphite used to make a conducting surface on the wax. In addition, there is a description of the formula and method of molding the wax masters, as well as an analysis of the defects in disc molds. There are indications that Harry R. Grimes worked with Dinwiddie on some of these experiments. Several notes and letters to and from Dinwiddie dating from 1917-1920 are inserted into the book. The front cover is labeled "Copper Plating Phonograph Records." The book contains 28 numbered pages; some pages are blank.

Courtesy of Thomas Edison National Historical Park.

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