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Details and Image

TypeModel No.MakerCountryConstruction
DateScale LengthArea of Use
American Steam Gauge & Valve Mfg. Co.
Aluminum and German Silver
ca. 1910
Determining Mean Effective Pressure from indicator diagrams

Notes: "The Bushnell-Coffin planimeter (named after John Coffin) is similar to the Ashcroft Averaging Planimeter in that it is a self-contained system, with an aluminum plate holding all the pieces, a card pad for the planimeter's tracing wheel to run on, multiple scales for different indicator spring strength, and a holder for the piece of paper with the indicator diagram. The weight for the planimeter is missing, and the tracing point is badly bent. "

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