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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.”
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.
Ref: Alumni Record of Wesleyan University (Hartford, 1883), p. cviii.
Currently not on view
Object Name
Physical Description
brass (overall material)
overall: 7 in x 18 in x 22 1/2 in; 17.78 cm x 45.72 cm x 57.15 cm
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
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
ID Number
catalog number
accession number
Credit Line
Wesleyan University
See more items in
Medicine and Science: Physical Sciences
Science & Mathematics
Data Source
National Museum of American History
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