Davy, Dr John (1790-1868), younger brother of scientist/poet Sir Humphry Davy (1778-1829), was a physiologist, anatomist, and writer, living at Lesketh How. He was the son-in-law of Mrs Eliza Fletcher, friend and correspondent of HCR (and Mrs Wordsworth) who lived formerly in Edinburgh and afterwards at Lancrigg, Grasmere. He and his wife appear often in these letters.