Sufficient has now been said to enable the reader to realise fully the arduous, exciting and often very hazardous nature of the work. Veteran sweepers listen for the loud hum of the wire which proclaims that a mine has been caught. Then comes an interval of a few seconds of suspense. Sometimes the mine bobs up within a few feet of the ship; at other times it is in the middle or bight of the wire, far astern, and half-way between the two sweeping vessels. When a mine is cut up a few shots from a 3-pounder, a shattering roar and the mine is destroyed. All that remains is a column of smoke reaching from sea to sky. It frequently happened that the mine became entangled in the sweeping gear and was unknowingly hauled on board with the sweep. When this occurred the position was fraught with extreme peril. Any roll of the ship might cause an explosion which would shatter to fragments everything and everyone within range. Safety lay in lowering the sweep gently back into the sea--an extremely difficult operation on a rough day. THE WAR CHANNEL This carefully guarded fair-way consisted of a 320-mile stretch of sea, extending along the east coast of England from the Downs to Newcastle, which was marked on the seaward side by a continuous line of gigantic buoys, two miles apart. It was patrolled day and night by hundreds of small warships, and swept from end to end by relays of sweepers acting in conjunction with each other from the different anti-submarine bases along the coast. The war channel formed a comparatively safe highway for all coastal shipping passing north or south through the danger zone, and vessels from Holland, Denmark, Norway and Sweden were able to cross the North Sea at any point under escort and proceed independently and safely along the British coast to whichever port could most conveniently accommodate them at the time of their arrival. It also relieved the terrible congestion on the railway lines between the north and south of England by enabling a coast-wise traffic to be carried on between the ports of London, Grimsby, Hull and Newcastle, as well as enabling the numerous Iceland fishing fleet to pass up and down the coast in comparative safety on their frequent voyages to and from the fishing grounds of the far north. From the naval or strategic point of view it more or less secured a line of supply for the Grand Fleet assembled in the misty north. Colliers, oilers, ammunition and food ships were able to proceed through the comparatively narrow section of the danger zone with a minimum of risk; and, had it been required, there was available a cleared passage for any squadron from the big fighting formations to come south at high speed to checkmate a bombardment or attempted landing on anything like a grand scale.