Ellis's personal correspondence, including a letter sent by a French officer to Sir G.B. Airy regarding an enquiry on magnetic observations at Greenwich from 1576 to the present; a letter from Ellis to H.P. Hollis on the controversy over the discovery of Neptune, including reference to Airy, J. Challis, H.H. Turner, and an article in 'Nature' by 'W.E.P.'; a letter from Hollis providing information on the sidereal period of revolution of Venus, Jupiter and Saturn; Ellis's manuscript notes on a comparison of chronometers at Greenwich and Mokattaru (Cairo) made in November 1874; and a letter from E.W. Maunder, Royal Observatory, Greenwich, containing sunspot statistics derived from Wolf's 'Relative Numbers' and measurements of photographs of the Sun. (MISSING)