In due course it was reported that the propellers of a believed-to-be German submarine, which, it could be said, had got out of her course in the dark, had fouled the fishing-nets belonging to some unknown boat. The local press was furious. Officialdom was stirred from its lethargy, much red tape and sealing-wax were expended, many politely worded notes passed between two Governments, and the event was soon forgotten by the Powers-that-be. But the fishermen concerned remembered all too vividly every detail and the horrible scare they had had, whilst they loudly lamented their lost gear. However, a Danish gunboat appeared a little more frequently round that particular part of the coast; mines, and yet more mines, were laid out; whilst the waters in question, which had so many times rippled round the boat of mystery, knew the activities of the conscienceless Hun no more. Meanwhile the Golden Argosy of unlimited profits from deep-channel trawling by night, as exploited by Messrs. Christian & Co., proved a ghastly financial failure. CHAPTER X THE MYSTERIOUS HARBOUR FRONTIER PROWLING--STARTLING RUMOURS--TERRIBLE WEATHER--EVADING SENTRIES--MAPPING THE WORKS--REFUGE WITH SMUGGLER--CONFIDENCES ON SUPER-SUBMARINES AND ZEPPELINS--A COUNTRY INN--PREPARING DESPATCHES--FORCIBLE INTRUSION--ARRESTED FOR A GERMAN SPY--SEARCH AND INTERROGATION--SUMMARY TRIAL--TRICKING THE SEARCHERS--COMMITTED FOR TRIAL--ESCAPE. Whilst prowling along the northern frontier of Germany in the early spring of 1915, with a companion whom I would have trusted with my life, we quite unwittingly got caught in a manner least expected. I had been over the frontier more than once, but never far into the interior. I had neither occasion nor object in so doing. I was at the time on the lookout for some Danish workmen who I knew had been employed on some of the important and secret war material of Germany. If I could meet them on German soil, so much the better; they would then be much more likely to open out and talk more freely than they would do if met elsewhere. I had had experience of this and was at the time most anxious to get corroborative evidence of some rather startling rumours which I had recently heard regarding the (later on called) Paris Big Gun. Whilst so prowling, as before mentioned, we heard speak of a certain harbour. The mysterious harbour, it was called, which no one might visit, which was jealously guarded, and which the Germans had every intention of occupying at an early date. Wild, speculative talk, perhaps, but it was enough to determine me to go and see for myself and so learn the truth and judge the possibilities from the facts gathered.