NICARAGUA severs relations with Germany, 19 My 7; declares war, 8 My 8 Nicholas, the Grand Duke, appointed Viceroy in the Caucasus, 5 S 5 Niemen, Battle of the, 26-28 S 4 Nieuport, Battle of, 10 Jl 7 _Niger_, H.M.S., sunk, 11 N 4 Nikolaieff occupied by Germans, 17 Mh 8 Nish captured by Bulgarians, 5 N 5; recaptured by Serbians, 12 O 8 Nitti, Sig., becomes Premier, 21 Je 9 Nivelle, Gen., succeeds Marshal Joffre, 12 D 6; is succeeded by Gen. Pétain, 15 My 7 Norongombe, a British victory at, 19 Jl 7 North Sea: _see_ Naval Actions, Jutland, Heligoland, Dogger Bank _North Star_, H.M.S., sunk, 23 Ap 8 NORWAY forbids the use of territorial waters to submarines, 13 O 6 _Nottingham_, H.M.S., sunk, 19 Au 6 Nova Alexandria, the Germans cross the Vistula at, 21 Jl 5 Novi Bazar captured by Germans, 21 N 5; occupied by Allies, 14 O 8 Novo Georgievsk captured by Germans, 20 Au 5 Noyon reoccupied by French, 21 S 4; retaken by Germans, 25 S 4; by the French, 18 Mh 7; evacuated by French, 25 Mh 8; retaken by French, 29 Au 8 _Nubian_, H.M.S., damaged, 27 O 6 Oberndorf, air-raid on, 12 O 6 _Ocean_, H.M.S., sunk, 18 Mh 5 _Oceanic_, H.M.S., lost, 8 S 4 Odessa occupied by Germans, 13 Mh 8 Oesel Island attacked by Germans, 12 O 7; they capture Arensburg, 13 O 7; fight a naval action, 14 O 7; occupy the island, 16 O 7 Okrida occupied by Bulgarians, 9 D 5 Olai captured by Russians, 7 N 5 Olita fort evacuated by Russians, 26 Au 5 Oppy captured by British, 7 O 8 Oppy line, fighting at the, 29 Ap 7, 3 My 7, 28 Je 7 _Orama_ sunk, 19 O 7 Orlando, Sig., becomes Premier, 28 O 7; resigns, 19 Je 9 Orsova, passage forced by Austro-Germans at, 23 O 5; occupied by Roumanians, 7 S 6; retaken by Austro-Germans, 23 N 6 Ortona bombarded by Austrians, 23 Jl 5 Ossowietz captured by Germans, 23 Au 5 Ostend occupied by British, 27 Au 4; the 7th Division disembarked at, 6 O 4; occupied by Germans, 15 O 4; bombarded by British, 5 Je 7, 22 S 7, 25 S 7, 21 O 7, 21 Mh 8; a British naval raid on, 23 Ap 8; H.M.S. _Vindictive_ sunk off, 10 My 8; air-raids on, 8 Mh 5, 10 N 6, 15 N 6, 17 N 6, 1 Je 7, 15 S 7; by French airmen, 8 F 5; reoccupied by Allies, 17 O 8 _Otranto_ sunk, 6 O 8 _Otway_, H.M.S., sunk, 23 Jl 7 Oulchy-le-Château captured by British, 25 Jl 8 Ourcq, the Battle of the, 9 S 4, 11 S 4 Ovillers, fighting at, 3-16 Jl 6 Painlevé, M., becomes Premier, 12 S 7; his Govt. defeated, 13 N 7 _Palembang_ sunk, 18 Mh 6