The stone wall, rising full thirty feet above low water-mark, was of massive construction. It had been additionally protected by concrete works and thousands of sand-bags. There were emplacements for heavy guns by the dozen, and for quick-firers by the hundred, while machine-guns bristled everywhere. There were plenty of evidences of the activity of the British guns and aeroplanes, for the wall had been repaired in fifty different places. Some of the havoc played by bombs was of recent origin, men, both Belgian and German, being employed to make good the damage. Almost abreast of the berth where the returned U-boat was lying was a hole twenty feet in diameter, and perhaps a dozen feet deep, while the wall on the seaward side was bulging ominously under the strain. At intervals, beneath the level of the outside parapet, several block-houses had been built on the Mole, machine-guns commanding the roadway on the breakwater. Evidently the Huns expected a landing, and with true Teutonic thoroughness were taking precautions accordingly. Within the harbour were swarms of small craft of all types--ocean-going torpedo-boats, patrol-boats, submarines, lighters, suction-dredgers, captured merchantmen, and paddle-wheelers. All, more or less, showed signs of being badly mauled, for, almost daily, British sea-planes swarmed overhead and let the Huns know that they meant to make things hot for the pirates' nest. At the present moment the guns were silent. Nevertheless, it was easy to see that Fritz was on thorns. Above the town floated four observation balloons; a Black Cross aeroplane flew discreetly along the sea-front, ready to hark back to its hangar on the first sign of the dreaded British sea-planes. From an elevated wooden tower on the extremity of the Mole, signalmen, brought specially from Kiel, swept the horizon with their telescopes. Anti-aircraft gunners were continually standing by, while in bomb-proof shelters artillerymen awaited telephonic orders to man their guns, should a 17-inch salvo from the monitors beyond the horizon announce that yet another strafe was beginning. Against the base of the parapet were bundles of barbed wire, one end of which was securely fixed to stout ring-bolts in the granite wall. On the inner edge of the Mole were massive iron posts, each post being abreast a corresponding roll of wire. This was a part of the German defences, for at night the wire was stretched across the Mole roadway, forming twenty or more barriers, in which narrow gaps were left to enable men to move to and fro. These barbed-wire defences were augmented by live wires, the whole forming a truly formidable obstacle should any attempt be made to storm the Mole.