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4 equilateral prisms
4 equilateral prisms

4 equilateral prisms

Datecirca 1890
Inventory Number1997-1-1700
ClassificationPrism
Subject
    Attributed to John A. Brashear 1840 - 1920
    Cultural Region
      Place of Origin
        Dimensionseach prism: 10 x 10 x 9 cm (3 15/16 x 3 15/16 x 3 9/16 in.)
        Material
          DescriptionThe four prisms have two polished faces with the other sides being painted black. They are equilateral with refracting angles of 60°.

          According to a note in the record, they were polished to within 1/4 wavelength flat.
          In Collection(s)
          Signedunsigned
          FunctionSuch prisms were used in spectroscopes to disperse light in order to study chemicals and stars. These are the kind typically found in astronomical spectroscopes.
          ProvenanceBowdoin College, 1890; gift to CHSI in 1992 courtesy of Professor E. LaCasce.
          Historical AttributesThese were ordered by Professor Hutchins of Bowdoin College around 1890 from the Brashear firm.
          1 equilateral prism
          1 equilateral prism
          John A. Brashear
          Date: circa 1890
          Object number: 1997-1-1700a
          4 rectangular prisms
          4 rectangular prisms
          American
          Date: 1900-1950
          Object number: 2007-1-0412
          prisms (2)
          prisms (2)
          American
          Date: 1930 - 1970
          Object number: 2003-1-0148
          60° liquid prism
          60° liquid prism
          John Browning
          Date: circa 1870
          Object number: 2007-1-0026
          1.875 x 2.25 inch rock salt prism in sealed tube
          1.875 x 2.25 inch rock salt prism in sealed tube
          John A. Brashear
          Date: 1916
          Object number: 1998-1-1323
          2 arsenal prisms
          2 arsenal prisms
          American
          Date: 1900-1950
          Object number: 2007-1-0413
          prism train for direct vision astronomical spectroscope
          prism train for direct vision astronomical spectroscope
          Alvan Clark and Sons
          Date: 1860-1870
          Accessories: square wooden case with velvet cushioning
          Object number: 1996-1-0029
          square wooden case for prism train
          square wooden case for prism train
          Alvan Clark and Sons
          Date: 1860-1870
          Accessories: square wooden case with velvet cushioning
          Object number: 1996-1-0029a
          9 assorted right-angle prisms
          9 assorted right-angle prisms
          American
          Date: 1900-1950
          Object number: 1998-1-0392
          pair of calcite prisms with different polarities
          pair of calcite prisms with different polarities
          American
          Date: circa 1900
          Object number: 1997-1-0848
          2 x 2 inch 60° prism on stand
          2 x 2 inch 60° prism on stand
          American
          Date: 1850-1900
          Object number: 1997-1-1695
          pair of 60° equiangular prisms
          pair of 60° equiangular prisms
          Edmund Scientific Corporation
          Date: mid 20th Century
          Object number: 1998-1-0336