Papers relating to the Anglo-German Yola-Cross River Boundary Commission, Nigeria and Cameroon, 1907-1909, comprising bound typescript account of the work of the Commission between Yola and Kwosa, Aug 1908, with unsigned geological report on the Nigerian-Cameroon Boundary, Yola to Cross River, 1907-1909, written in [1909]; photographs, 1907-1909, bound with 'Two years on an Anglo-German boundary commission in West Africa', typescript by Downes, [1909] and 'Nigeria: delimitation of boundary between Yola and the Cross River, 1907-9', Command paper 5368, printed by HMSO in 1909. With the Nigerians in German East Africa (Methuen and Co, London, 1919), special edition bound with typescript copies of press reviews, 1919. Photographs relating to his service with 2 Royal Sussex Regt, Crete, 1906, bound with an account of his service, written in 1915. Photographs of Sinai, 1909-1911, mainly landscapes and people.

Diaries, 1901-1968; papers and photograph albums relating to the Boer War and photography in military reconnaissance, including an unpublished manuscript, 1897-1902, service in Northern Nigeria on the Anglo-French Boundary Commission, 1902-1904, West Africa, 1903, West Indies, 1902 and Ordnance Survey of Scotland, 1904-1909; papers relating to the introduction and use of chemical warfare during World War One, 1914-1918, and on the North West Frontier, India, 1919-1920 andphotographs taken on the Western Front, 1914-1915 and 1919; articles written as Director of Irish Propaganda during the Anglo-Irish War, 1921; papers concerning appointments as Colonel Commandant and Representative Colonel Commandant, 1937-1944; papers concerning writing and publication of 'Gas!' The story of the Special Brigade (Blackwoods, 1934) and Commonsense and ARP (C Arthur Pearson, 1939) and draft chapters and photographs concerning the unpublished manuscript 'Adventures of an Engineer Subaltern' dealing with military career, 1897-1903; personal correspondence and papers relating to memorial service, 1900-1981; glass and film negatives covering career, 1897-1920.