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<rdf:Description rdf:about="https://catalogues.royalsociety.org:443/CalmView/record/catalog/HS/19/269" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
  <dc:title>Copy letter, from Augustus De Morgan to Joseph Powell, dated at 91 Adelaide Road</dc:title>
  <dc:description>Copy letter in De Morgan's hand. Comments on two papers likely on optics written by Powell. Confirms the mathematics are correctly managed but the issues is with the number of sines that are required in the formula. Cites Lambcot on photometry and Herschel on light as authorities and references.
Likely forwarded to Herschel for reference.</dc:description>
  <dc:date>17 February 1863</dc:date>
</rdf:Description>