Diffraction Grating

Diffraction Grating

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This concave metal grating probably belonged to Samuel Pierpont Langley, director of the Allegheny Observatory and professor of astronomy at the Western University of Pennsylvania (now the University of Pittsburgh). It probably came to Washington in 1887 when Langley became the third Secretary of the Smithsonian Institution.
The inscription reads "plate polished and corrected by J. A. Brashear Pittsburgh, Mar. 1886 Radius 64 Ruled by Schneider on Rowland engine Johns Hopkins University April 1886 - lines to in temp-".
Currently not on view
Object Name
diffraction grating
date made
Rowland, Henry A.
Brashear, John A.
place made
United States: Maryland, Baltimore
overall: 4 3/4 in x 6 3/4 in x 7 3/4 in; 12.065 cm x 17.145 cm x 19.685 cm
overall: 4 3/4 in x 6 3/4 in x 7 3/4 in; 12.065 cm x 17.145 cm x 19.685 cm
ID Number
catalog number
accession number
Credit Line
Smithsonian Astrophysical Observatory
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Medicine and Science: Physical Sciences
Science & Mathematics
Data Source
National Museum of American History
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