4 equilateral prisms
Date: circa 1890
Inventory Number: 1997-1-1700
Classification: Prism
Subject:
Attributed to: John A. Brashear (1840 - 1920)
Cultural Region:
Place of Origin:
Dimensions:
each prism: 10 x 10 x 9 cm (3 15/16 x 3 15/16 x 3 9/16 in.)
Material:
Description:
The 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.
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.
Historical AttributesThese were ordered by Professor Hutchins of Bowdoin College around 1890 from the Brashear firm.
ProvenanceBowdoin College, 1890; gift to CHSI in 1992 courtesy of Professor E. LaCasce.