This grouping relates to Henry Cavendish's work with telescopes and light. There is a one-page index at the front of the bundle and a note, both in Dean George Peacock's handwriting. Dean George Peacock (1791-1858) was an English mathematician and Anglican cleric. He saw and made notes on some of Cavendish's papers in the early 1850s.
Reference numbers HY/5/1-2 were not been used in the Royal Commission on Historical Manuscripts catalogue. These references are now used for the index and note from Peacock.
HY/5/3-13 were arranged prior to 2024. They are described in Thorpe, Sir Edward "The Scientific Papers of the Honourable Henry Cavendish, F.R.S" (1921; Cambridge; Cambridge University Press) Vol II Chemical and Dynamical, p401 but are not described in the same order as they are arranged. The order in Thorpe 1921 Vol II is: HY/5/7, HY/5/9, HY/5/10, HY/5/11, HY/5/12, HY/5/4, HY/5/13, HY/5/6, HY/5/5.
HY/5/14 describes Cavendish's thoughts on atmospheric refraction.