[Miscellaneous wartime (WW1) collection of chiefly reports, mostly from the M.I.D.'s Anti-Aircraft Experimental Section (at Rochford and at Orfordness) and Acoustical Research Section (at Imber Court), re sound location and allied subjects, complemented by material, later compiled by Science Museum staff, relating to echo-sounding, sound ranging, hydrophones etc ./ Ministry of Munitions, Munitions Inventions Department. 1 box]