Spectroscope
notes: label: Description
content: This spectroscope, designed for use with an astronomical telescope, was given to Wesleyan University, in Hartford, Connecticut, in 1880. An inscription reads “IN MEMORIAM. DAVID H. WALKLEY, Graduated June 27th 1878. Died Sept. 15th 1878.”
label: Description
content: The diffraction grating inside the spectroscope is inscribed “Ruled by Schneider on Rowland’s engine Johns Hopkins University 14,438 lines to the inch, 1887. Every hundredth line extended on one side, plate polished and corrected by J. A. Brashear Allegheny, Pa. U.S.A. 1887. Grade AE II Bright curve in 4th.” Henry Rowland, the first professor of physics at The Johns Hopkins University, built an engine for ruling the parallel lines needed for diffraction gratings. This engine became operational in March 1882, and Rowland gratings were soon in use around the world. In many instances, these gratings were on concave metal plates, figured and polished by John A. Brashear in Allegheny, then a suburb of Pittsburgh.
label: Description
content: Ref: <i>Alumni Record of Wesleyan University</i> (Hartford, 1883), p. cviii.
label: Location
content: Currently not on view
setName: label: See more items in
content: Medicine and Science: Physical Sciences
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content: Science & Mathematics
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content: Optics
creditLine: label: Credit Line
content: Wesleyan University
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.328770
label: catalog number
content: 328770
label: accession number
content: 277481
objectType: label: Object Name
content: spectroscope
physicalDescription: label: Physical Description
content: brass (overall material)
label: Measurements
content: overall: 7 in x 18 in x 22 1/2 in; 17.78 cm x 45.72 cm x 57.15 cm
label: Measurements
content: overall: eyepiece: 3 1/8 in x 4 1/2 in x 2 in; 7.9375 cm x 11.43 cm x 5.08 cm
label: Measurements
content: overall: spectroscope: 6 7/8 in x 21 in x 17 5/8 in; 17.4625 cm x 53.34 cm x 44.7675 cm