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<rdf:Description rdf:about="https://catalogues.royalsociety.org:443/CalmView/record/catalog/MS/377/1/4" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
  <dc:title>Letter from Herbert F Angus, H F Angus and Company, 83 Wigmore Street, Cavendish Square, London, to William Fletcher Barrett </dc:title>
  <dc:description>Advises against trying to take out American patents on his opthalmic apparatus. Suggests methods of promoting the devices in Britain. The leakage in the light threshold apparatus may be solved by inserting hollow wedges filed with solution.</dc:description>
  <dc:date>16 April 1909</dc:date>
</rdf:Description>