Mackensen storms Russo-Rumanian positions north of Focsani and takes 1,300 prisoners. Slight British progress west and south-west of Lens. National Ministry formed in Russia under M. Kerensky. Changes in the Admiralty announced. Vice-Admiral Sir Rosslyn Wemyss appointed Second Sea Lord in succession to Admiral Sir Cecil Burney, Mr. Alan Garratt Anderson to be Controller, and Sir Oswyn Murray to be Permanent Secretary in succession to Sir W. Graham Greene, transferred to Ministry of Munitions.