The Navy, though it had vanished into the unknown, was very busy, and was doing its work wonderfully well. Our light cruisers, destroyers, and submarines were continually watching the movements of the enemy. They are, as you know, the "eyes and ears" of the Fleet, and it was their business to inform Sir John Jellicoe the moment that enemy ships attempted to leave their harbours, so that he might bring them to action. Further, our warships had to prevent commerce raiders from slipping out and creeping into the ocean between Norway and the Orkneys in order to prey on the trade routes. Many of our warships were busy night and day examining neutral ships, to see that they did not smuggle what we call contraband of war[90] into Germany, while others acted as convoys to troopships and supply ships, or as pilots to friendly traders passing through the mine-fields. Fleets of trawlers, as you know, were engaged in sweeping up mines. The Navy, you observe, was fully occupied in the North Sea, "bottling up" the German fleet, and preventing war supplies from reaching the German ports; while, out on the ocean, our cruisers were policing the trade routes, capturing the enemy's merchant ships, and chasing his commerce destroyers. The best proof that the Navy was doing its work in the best possible way was the absolute helplessness of the Germans to impede our overseas trade, or to interfere with the movements of our troops in all parts of the world. [Illustration: A British Destroyer in action.] Though there was no chance of a Trafalgar in the North Sea, there was an engagement in the month of August 1914 worthy of the name of a battle. I have kept the story of this sea fight for the present chapter. Three hours after we declared war two British submarines, E6 and E8, were on their way to the Bight of Heligoland on a scouting mission, and from that time onward a constant watch was maintained on the doings of the enemy's fleet in his own waters. Our submarines pushed right into the mouth of the Elbe, discovered the numbers and movements of the enemy's patrols, examined his anchorages, and picked up much useful information. Of course the Germans did not allow them to do this work in peace. They were constantly attacked by gun fire and torpedoes, and hunted by destroyers. The submarines discovered that every night a flotilla of German light warships and destroyers was in the habit of coming out from Heligoland, or from one of the ports behind it, and cruising for some hours in the North Sea. As soon as Sir John Jellicoe heard the news, he made plans for a great "round up" of this night-cruising flotilla. His object was "to cut off the German light craft from home, and engage them at leisure in the open sea."