Calculating Disc, Sherrill Compass Deviation Calculator, Felsenthal FAO-2

Calculating Disc, Sherrill Compass Deviation Calculator, Felsenthal FAO-2

Usage conditions apply
According to marks on this small plastic instrument, it was “furnished” by the Sherrill Research Corporation of Peru, Indiana, and copyrighted in 1944. At that time, Sherrill was making compasses for the U.S. military and sold this calculator to easily correct compass readings. Instructions are on it.
According to a tag received with the object, Felsenthal made the instrument for the U.S. Army as the FAO-2 and sold it in 1943.
Currently not on view
Object Name
Calculating Disc
date made
ca 1943
ca 1944
Felsenthal Instrument Co.
Felsenthal Instrument Co.
Physical Description
plastic (overall material)
overall:.1 cm x 8.5 cm x 11.4 cm; 1/32 in x 3 11/32 in x 4 1/2 in
ID Number
catalog number
accession number
Credit Line
Gift of Ben Wharton Rau and Margery Felsenthal Rau
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Measuring & Mapping
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object