<?xml version="1.0" encoding="utf-8"?>
<rdf:Description rdf:about="https://catalogues.royalsociety.org:443/CalmView/record/catalog/AP/64/9/2" 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Unpublished diagram, 'Focal curves for a system of two lenses at varying distances apart' by George James Burch</dc:title>
  <dc:description>A diagram, labelled diagram 1, showing a series of overlapping lines and cruves indicating the locus of centres, locus of vertices and perspective focal line.

Subject: Optics</dc:description>
  <dc:date>1886</dc:date>
</rdf:Description>