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<rdf:Description rdf:about="https://catalogues.royalsociety.org:443/CalmView/record/catalog/HS/18/15" 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 James Thomas Walker to Sir John Herschel, dated at 1 Cromwell Road, South Kensington</dc:title>
  <dc:description>Autograph letter signed by sender. Sent John Frederick William Herschel 'Index Chart' of Great Trigonometrical Survey of India. Compares five triangulation methods: longitudinal series, George Everest's, G. B. Airy's, that of John Frederick William Herschel's son John, and minimum squares. John Frederick William Herschel's son and bride avoided cyclone that destroyed Calcutta Observatory.</dc:description>
  <dc:date>9 December 1864</dc:date>
</rdf:Description>