Concave Rowland diffraction grating on speculum metal, grating area 84 x 41 mm, with scratched markings reading 'Plate prepared at the Astronomical / & Physical Instrument Works of / J A Brashear Allegheny, Pa USA / 1899' and 'Ruled on Rowlands Engine / Johns Hopkins University Baltimore Md 1899 / Rad = 10 ft', other markings illegible, in wooden cradle in wooden case.
- Object Number:
grating block: 14 x 102 x 100 mm
case, overall: 108 x 137 x 150 mm
- furnishing and equipment
- tools & equipment
- optical instrument
- optical instrument component
- Imperial College of Science,Technology & Medicine (Spectroscopy Group)
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