Concave Rowland diffraction grating on speculum me

1898 in Allegheny City and Baltimore
Henry Augustus Rowland

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Concave Rowland diffraction grating on speculum metal, grating area 49 x 34 mm, in wooden case marked 'V209.' Scratched markings on grating illegible. Manuscript note inside the case reads 'Ruled on Prof. Rowlands Engine Johns Hopkins University Baltimore Maryland U.S.A. 1898 Plate prepared at the Astronomical Physical instrument works of Mr J Brashear, Allegheny, Tennessee (sic) U.S.A. 1897 14438 lines to 1 inch 568 lines to 1 mm. Very bright one side. Definition excellent. V209'. This is repeated in German. A paper label on the box marked in German indicates (according to the donor) that the grating came from Paschen's laboratory.


Object Number:
speculum metal and wood
case: 24 x 75 x 75 mm
grating block: 9 x 61 x 61 mm
diffraction grating - reflection
  • furnishing and equipment
  • tools & equipment
  • optical instrument
  • optical instrument component
Imperial College of Science,Technology & Medicine (Spectroscopy Group)

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