October 17th, 1914

- In Flanders today the British III Corps advances to occupy the town of Armentières, while just to the south a brigade of II Corps seizes a portion of Aubers Ridge.  A further French cavalry corps also arrive at Ypres to reinforce the Entente line.  Though the advance is slow, both Ferdinand Foch and Sir John French see no reason to deviate from the overall objective of the operation - i.e. a sweep to and around Lille to outflank the German line.  Aerial reconnaissance today reveals only that elements of the German III Reserve Corps are moving northwards, concentrating along the Channel coast.  The British and French commanders have no idea that the reason for this redeployment of III Reserve Corps is to make way for the four new reserve corps that are about to descend on the Entente line.

- Ludendorff today orders Mackensen's XVII Corps to hold a line near Lovich west of Warsaw to cover the Russian 2nd Army advancing out of the city, in order to protect the northern flank of the rest of 9th Army.

- Admiral Jellicoe receives a report today that a German submarine has been sighted inside Scapa Flow, the main anchorage of the Grand Fleet.  Though the report is later deemed false, it comes on the heels of the sinking of the armoured cruiser Hawke on the 15th and the three armoured cruisers sunk on September 22nd, and his fear of the submarine threat reaches a breaking point.  He informs the Admiralty that he no longer considers Scapa Flow safe for use, and insists that he be allowed to take the fleet further west, away from the submarine threat.  The Admiralty assigns the harbours at Loch-na-Kael on the Scottish west coast and Lough Swilly on the northeast Irish coast for use by the Grand Fleet.  Both have narrow entrances that are easily defended, making it more difficult for submarines to penetrate them.  Still, it moves the Grand Fleet further away from the North Sea, and it is worth noting that this 'retreat' is forced by German submarines while its High Seas Fleet remains in port.

- Tonight the German submarine S90 attacks the Japanese cruiser-minelayer Takashio at Tsingtao.  Three torpedoes are launched, which strike the ship and detonate its cargo of mines.  The resulting explosion destroys the ship and kills all but three of its crew of 253.  However, the concussion wave from the blast cracks the hull of S90, which has to be abandoned.