Spirit Duplicator ...
"This machine printed from a "master" created in the same manner in which hectographic master sheets for spirit duplicators were made, but considerably before their introduction" (Rhodes and Streeter 109).
Gardiner, A. W. Typewriting and Office Duplicating Processes. New York: Focal Press, 1968.
Rhodes, Barbara J. and Streeter, William W. Before Photocopying : The Art and History of Mechanical Copying, 1780-1938: A book in two parts'. New Castle and Northampton: Oak Knoll Press and Heraldry Bindery, 1999.