Nancy,
 
If memory serves, the Ohio Historical Society has one or more illustrated
catalogues of the Leffel Co., which was in Springfield, Ohio.  There is also a
little bit of information in the chapter on "The Turbine Waterwheel and the
Roller System" in D.W. Garber's <Waterwheels and Millstones: A History of Ohio
Grist Mills and Milling>, published by the Ohio Historical Society.  This
includes a couple of letterheads illustrating a Lefel turbine and one
manufactured by Stout, Mills & Temple, of Dayton, Ohio.
 
Jim Murphy
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