Drainage Works of Fortified Towns - carried out in 1875-1885 including 1) letter dated 03.08.1870 from Alex Milne, Admiral, Commander in Chief to HE Lt Gen Sir Patrick Grant 2) letter from Admiral Superintendent A Copper Key to Sir A Milne 3) unsigned letter dated 11.04.1877 from Admiralty to Treasury 4) Letter dated 25.04.1877 from Treasury to Admiralty signed William Law.