(1) Lunar physics

Miscellaneous correspondence with various individuals concerning different aspects of lunar physics, 1886-1901, including changes in the appearance of lunar craters, unexplained lights, glows on the Moon's surface, the fall of meteors on the Moon's surface and possible effects on the Earth, the subject of why the Moon is addressed as 'she', and the origin of lunar mountains.

(2) Planetary physics

Miscellaneous correspondence with various individuals concerning planetary matters, 1892-1926, including a paper on the relative motion of Saturn's rings; C. Denham on Venus seen in daylight; E.J. Stone on the opposition of Mars, 1892; a telegram from Reuters regarding work on Mars in the U.S.A. and the canals seen at the Lick Observatory; S. Chaloner on theories to account for Martian markings; A.G. Drummond regarding bright spots on Mars's dark side; Mrs Brinkley on Mars being in a 'state of fire'; Miss Clay on a bright object seen; Dr Knight regarding canals on Mars; R. Hughes on the transit of Mercury; and J. Scott's observation of the transit of Mercury.

Other subjects covered in the correspondence are as follows:

1895: R. Belfitt on a bright object seen, possibly Venus; W.H. Tate on places of Jupiter, Mars and Venus; J. Moore on measures of Jupiter's diameter; W.J. Baily on Mars; and H. Griffiths on drawings of Jupiter.

1896: W.J. Baily on Mars and H. Griffiths sends drawings of Jupiter and Venus.

1897: H. Griffiths sends drawings of Mars and Jupiter.

1898: T. Hewiston's request for a photograph of Mars and J.J. Pierce on Mars's polar caps.

1899: M. Serge Socolow sends his work 'Correlations regulieres des planetarre'.

1900: F. Hughes, Mrs Summers and J.W. Hurst on a bright object seen (Venus).

1901: P.A. Shaw on what a Martian observer would see of Earth, a cutting from the 'Daily News' of 31 December 1900 on signals from Mars, L. Dominion on the reception of a telegram from Mars, W.J. Knight on Saturn's rings, and J.M. Hewiston's request for a photograph of Mars.

1902: J. Wallamay on the colours of planets.

1903: W. Cottriel's request for assistance with his work on solar rotation.

1904: Serge Socolow on his work on planetary disturbances.

1905: The Revd Sparkes on the satellites of Mars and R. Parry on measuring the polar 'compression' of Venus.

1906: Scriven Bolton sends drawings of Jupiter.

1908: A.R. Hassard on the axial rotation of planets and Serge Socolow on planetary theory.

1909: G. Bureton on signalling to Mars and E. Shaer on Saturn's rings.

1912: Sir D. Gill on observations by Todd on Saturn's rings and H. Macauly Fosnett on Saturn's rings.

1915: Circular from W.H. Pickering regarding his work on Mars at opposition.

1917: A.E. Joseph on communicating with Mars.

1918: Miss E.C. Taylor's request for information on Mars.

1920: C.H. Rowland on the case of a trans-Neptunian planet.

1921: W. Munro on oppositions of Saturn, 1576-1588, and G.C. Izard on the Martian atmosphere.

1922: W. Trimble on messages from Mars.

1925: G. Forbes on perturbations of Neptune due to a trans-Neptunian planet.