Lot Essay
Andrew Pritchard is known for his work on diamond and sapphire objective lenses in the 1820s and 1830s (see Turner, G L'E: 'The Rise and Fall of the Jewel Microscope 1824-1837' (in Microscopy: The Journal of the Quekett Microscopical Club 31 (1968)), reprinted as Chapter 5 in the same author's Essays on the History of the Microscope (Oxford, Senecio, 1980).