Letters submitted to the RGO by the general public and deemed unworthy of a response. Most have no clear astronomical question or request, and many are submissions of personal theories, musings, or random thoughts, or relate to astrology or religious beliefs (e.g. letters asking the distance to heaven or writing on a perceived link between apparitions at Lourdes and Halley’s Comet). Some letters are almost unintelligible. The majority are from individuals who wrote repeatedly to the RGO, often over a number of years.

Enclosures include manuscript writings of theories, e.g. Mc Kinley Martin’s ‘The Bicorpuscular-Photon Hypothesis’ and Jean Lefevre’s ‘Ětre humains en peril ou du mèpris de la vie humaine’, diagrams, an offprint titled, ‘The cause of gravitation’ by A.B. Rendle, and a news cutting.

Consecutive numbering is the archivist's.