A Georgian Camera Lucida, English, c.1820, unsigned but similar to those made by Cary or Dollond, the lucida with table clamp to the base, telescopic drawer tube engraved 2, 3, 4, 5, 7, 10 and D, the prism head with 2 magnifying lenses and a shade, in a sharkskin covered case, case 23cm wide. The Camera Lucida - also known as the "light chamber," is an optical device that was patented by William Hyde Wollaston in 1806. Its purpose is to assist in the precise rendering of objects during sketching. The instrument comprises a small stand supporting a four-sided prism, positioned above a sheet of paper which superimposes the image viewed over the paper. This allows the artist to sketch the scene in front of them.