5. Telescopes (continued).
5/14.3. Results from 5/12, arranged by subject, from which the sections of 5/14.1 have been copied.
5/15.1. Engraving of the large 20ft telescope, 1794.
5/15.2. Nine prints taken from 5/15.1.
6. Physics (including theoretical optics).
6/1.1. 'Investigation of the cause of that indistinctness of vision which has been ascribed to the smallness of the optic pencil.'
6/1.2. Notes and calculations relevant to 6/1.1.
6/2. 'Investigation of the powers of the prismatic colours to heat and illuminate objects.'
6/3. 'Experiments on the refrangibility of the invisible rays of the Sun.'
6/4.1. 'Experiments on the solar and on the terrestrial rays that occasion heat [Part I].'
6/4.2. Second part of the paper on the solar and on the terrestrial rays that occasion heat, with 'Appendix to the Paper on the power of penetrating into space by telescopes'.
6/4.3. Calculations relating to the second part of a paper on the solar and on the terrestrial rays that occasion heat. There are also two letters: Patrick Wilson to William Herschel, 5 January 1801, and Herschel to Wilson, 9 January 1801.
6/5. 'Experiments for investigating the cause of the coloured concentric rings discovered by Sr. I. Newton', with a page of 'Calculations belonging to the 1st part of the paper on the Newtonian rings'.
6/6.1. Continuation of 'Experiments for investigating the cause of coloured concentric rings'.
6/6.2. Calculations relating to second part of the paper on the Newtonian coloured rings.
6/7.1. Supplement to the first and second parts of the paper on Newtonian coloured rings.
6/7.2. Calculations relating to the third part of the paper on Newtonian coloured rings.
6/8. 'Philosophical Experiments', 1780, 1794, 1798 and 1805, with some additional papers.
6/9. 'Hints. Desiderata. Experimts to be made.'
6/10.1. 'Optical Experiments', 9 April 1792 - 9 October 1809, with two pages of a tract 'On the modifications of the flection of the rays of light'.
6/10.2. Calculations relating to optical, telescopic, prismatic and other experiments.
6/11. 'Experiments on Light and Heat' (continued in RGO 35/171/24).
6/11.1. No. 1: 1-391, 17 January 1799 - 26 June 1800.