Correspondents on defence inventions and suggestions from the general public include: K N Coates [Assistant Private Secretary to the Minister for the Co-ordination of Defence] (4); Vernon Bovenizer, Private Secretary to the Secretary of State for War (2); [Edward] Jerome Dyer; Harry Sellar [Private Secretary to the Minister for the Co-ordination of Defence] (2); P Warburton, [Assistant Secretary], Committee of Imperial Defence (4); Lieutenant-General Sir Hugh Elles, Master General of the Ordnance, on trials for armour- piercing bullets (2); Arthur Comyns Carr; Guy Eden, Political Correspondent for the Daily Express, on shadow air industry contracts; Desmond Morton [Director, Industrial Intelligence Centre]; Field Marshal 10th Lord Cavan [earlier Lord Kilcoursie] on the use of barrage balloons in air defence; Hugh Frewen on armour-piercing bullets.Other subjects include: camouflage; bombsight development; aircraft armaments and explosives; machine gun mounts; battleship defence from air attack.Also includes: press cutting from the Daily Mail on developments in German bombers; press cutting on infra-red searchlights; statement by Marshall Tate on the lack of access to Service officials, and on his aero engine developments; note by Desmond Morton on magnesium production; paper by J H Anderson on the effects of the Government defence programme on the engineering industry; copies of correspondence by Violet Pearman [Secretary to WSC].