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<rdf:Description rdf:about="https://catalogues.royalsociety.org:443/CalmView/record/catalog/MS/877/3/19" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
  <dc:title>Lecture, 'Double refraction on electromagnetic theory,' by Alfred W Porter</dc:title>
  <dc:description>Discusses the optic axis and provides an examination of it  through a negative crystal. Discusses the  relations between directions, and  examines wave surfaces. </dc:description>
  <dc:date>[1921]</dc:date>
</rdf:Description>