German methods of warfare had meanwhile been illustrated by the attempt to sink the French steamer _Amiral Ganteaume_, crowded with refugees from Calais, in the English Channel (Oct. 26), and indirectly by the terrible wreck of the British hospital ship _Rohilla_ off Whitby (Oct. 30), caused mainly by her keeping close inshore to avoid mines in an easterly gale, though she was believed to have struck one before stranding. On November 2 the Admiralty issued a warning that the Germans, through the agency of some merchant vessel under a neutral flag, had scattered mines indiscriminately on the route between America and Liverpool _via_ the north of Ireland; the White Star liner _Olympic_ had escaped them only by pure good luck; and, in view of the German practice, the whole of the North Sea must now be declared a military area; after November 5 any ship passing a line drawn from the north point of the Hebrides through the Faroes to Iceland must do so at its peril. Within the North Sea arrangements were made to prescribe safe routes for vessels trading with neutral countries, but even a slight deviation would be dangerous. It was afterwards stated that the _Olympic's_ escape was caused by her response to a call on October 27 from one of the newest British battleships, which had struck a mine off Ireland while on patrol duty, and whose crew she had been able to save, though not the ship. The _Olympic_ was detained for some days in Lough Swilly, no one being allowed to land, and was then taken to Belfast. Particulars reached the American papers by mail and were published there with photographs and in neutral papers also, and rumours of the disaster had circulated in England for some time. But the Admiralty gave the story no official confirmation, and the name of the ship in question remained in the Navy List. Apart from this, however, the naval war was sensibly drawing nearer to Great Britain. On October 27 the Admiralty closed all but one of the approaches to the Thames, and ordered vessels in a specified area of the estuary to anchor during the night and show no lights; H.M.S. _Hermes_ was torpedoed in the Downs, only two miles off Deal, on October 31; and on the morning of November 3 a German squadron fired on H.M.S. _Halcyon_ off Yarmouth, wounding one man, but were driven off by the approach of other British ships, and pursued by light cruisers, which failed to engage them. In retiring the Germans threw out mines promiscuously and the British submarine D 5 and two steam drifters were sunk. Rumour connected this advance with a German attempt at a raid.