Channel: Monitor HMS Glatton scuttled at Dover following magazine explosion and fire. Coastal submarine UB-103, sighted by British blimp SS 21 (Pilot US Ensign NJ Learned), sunk by several Royal Navy drifters’ depth charges off Cap Gris Nez.
Meuse: St Mihiel salient fully straightened out for 7,511 US and 597 French casualties (15,000 beds available), 15,000 PoWs and 450 (or 443) guns taken. Germans commit 4 reserve divisions. Metz fortress guns fire (September 15), but c.400,000 Americans now switched 60 miles northwest.
USSR: Lenin recovers from gunshots, attends meetings (until September 17), but moves to Gorki (September 24 or 25) to convalesced until mid-October.
Macedonia: Serb Yugoslav Division attacks Mt Kozyak all day (inside Bulgar 3rd line) and finally takes it, but German 13th Saxon Jaeger battalion covers breach. Scholtz cables Hindenburg, asking for German divisions from Western Front; request forwarded to Austrians, who hedge. Bulgar 2nd Division withdraws to 3rd line without warning.
Bulgaria: Tsar Ferdinand replies to General Lukov peacefeeler suggestion ‘Go out and get killed in your present lines’.
Italian Front: Italian raid north and northwest of Mt Grappa takes 300 PoWs and some MGs, counter-attacks beaten on September 17.
Trans-Jordan: 6 RAF DH9s raid Deraa for first time; 8 German planes from there cause Arab Army only 2 casualties thanks to BE12 (destroyed).
Western Front: RAF destroy 8 German aircraft for loss of 4 over BEF Third Army but, overall, Germans claim 59 Allied planes for loss of 10.
Germany: 7 RAF Handley Pages lost on raids on Cologne, Saarbruecken and Trier etc, 6 of them lost to anti-aircraft guns (16,063 rounds fired and 173 searchlights in action, night September 16-17).
USA: Wilson rejects Burian ‘Peace Note’ (Vienna receives on September 19).
Britain: Balfour calls Austro-German offers unacceptable. King George V cables President Wilson with congratulations on St Mihiel salient removal.
Germany: Count Hertling tells Conservative leader that Austrian peace move has prejudiced Dutch mediation.
Japan: Government recognizes Czechs as belligerent Allies.