SECOND BATTLE OF YPRES (until May 13): Battle of Gravenstafel (Ridge) (until April 23). Big Berthas shell Ypres. FIRST WESTERN FRONT POISON GAS ATTACK begun by German Fourth Army at 1700 hours near Langemarck: 3 1/4 mile front lined with 4,000 chlorine cylinders. 168t of chlorine released within 5 minutes. 2 German divisions attack French 45th Algerian Division supported on right by Canadian 1st Division, near St Julien. Germans wearing respirators cautiously ‘mop up’ on Pilkem Ridge, taking c. 2,000 PoWs and 51 guns. French Colonials flee across canal causing 800 yards gap in Allied line. Fierce fighting for Canadian wood west of St Julien; finally secured by Germans.
Serbia: Royal Navy steam picketboat launches 2 torpedoes at Austrian Danube Flotilla anchorage (night 22-23); British believe monitor Koros sunk, actually just a dummy vessel.
Mesopotamia: Townshend, new GOC 6th Indian Division, arrives Basra.
Anglo-Norwegian Oil Agreement.
Britain: Admiral Lord Beresford criticizes Dardanelles operations in House of Lords.