Diary for Thursday, May 4, 1916:
Eastern Front: IM heavy bomber Ilya Murmometz II (Pankratiev) flies first of 5 successful armed reconnaissance missions during May over Yazlovetch-Bugatch and Yazlovetch-Rusilov sectors and helps capture of Yazlovetch.
Germany: Rules of cruiser warfare to be observed by U-boat commanders if ships do not try and escape or resist.
Adriatic: French submarine Bernouilli blows stern off Austrian destroyer Csepel at Cattaro entrance.
Germany: Government Sussex ‘pledge’ reply to US note, will not sink vessels without warning, US accepts on May 8.