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<rdf:Description rdf:about="https://catalogues.royalsociety.org:443/CalmView/record/catalog/AP/64/9/3" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
  <dc:title>Unpublished diagram,'Showing the positive and negative principal points, and principal foci of a system of two lenses placed in contact and gradually moved apart' by George James Burch</dc:title>
  <dc:description>A diagram, labelled diagram 2, showing a number of asymptotic lines on an X and Y axis.

Subject: Optics</dc:description>
  <dc:date>1886</dc:date>
</rdf:Description>