1 equilateral prism
Datecirca 1890
Inventory Number1997-1-1700a
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 prism 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.
According to a note in the record, they were polished to within 1/4 wavelength flat.
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.
John A. Brashear
Date: 1916
Object number: 1998-1-1323
Alvan Clark and Sons
Date: 1860-1870
Accessories: square wooden case with velvet cushioning
Object number: 1996-1-0029
Alvan Clark and Sons
Date: 1860-1870
Accessories: square wooden case with velvet cushioning
Object number: 1996-1-0029a
