Concave Rowland diffraction grating on speculum me

1894 in Baltimore and Allegheny City
Henry Augustus Rowland

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Concave Rowland diffraction grating on speculum metal, grating area 84 x 39 mm, with scratched markings reading 'Plate prepared at the Astronomical / Pysical (sic) Instrument Works of / J A Brashear, Allegheny, PA USA / 1894' and 'Ruled on Rowland's / Engine Johns Hopkins University / Baltimore Md / USA / 1894', in wooden case marked 'V.211.', with '15000 per inch' pencilled inside the base. A paper label on the case marked in German indicates (according to the donor) that the grating came from Paschen's laboratory


Object Number:
speculum metal and wood
box: 25 x 118 x 118 mm
grating block: 13 x 99 x 101 mm
diffraction grating - reflection
  • furnishing and equipment
  • tools & equipment
  • optical instrument
  • optical instrument component
  • diffraction grating
Imperial College of Science,Technology & Medicine (Spectroscopy Group)

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