Within an hour and twenty minutes of the despatch of the wireless message to London a reply was received that threw considerable light upon the movements of the modern buccaneer. Karl von Harburg had caused a report to be sent to the news agencies to the effect that he had destroyed the only submarine that stood between him and his definite aim, and now he was at liberty to do what damage he wished to the naval and mercantile fleets of the world, irrespective of nationality or any other consideration. With this object in view he had sunk a French liner off Cape Guadafui, after ransacking her strong rooms. He had even been compelled to substitute gold ingots for the common metal ballast of his craft. Silver he would hardly look at. This ultimatum was received with amazement and in dismay shipping circles. It seemed in vain to appeal for armed warships to destroy the "Vorwartz," since she could keep below the surface for days at a stretch, and could descend deeper than any submarine with the exception of the "Aphrodite." And Karl von Harburg believed that his rival was no longer in existence. There was no doubt that Karl von Harburg was a madman. However successful his raids on shipping might be, however great his hoards of ill-gotten gold, he would never be able to make use of his wealth. He was a world-wide pariah. No civilized country would give him refuge. Even his base in the Island of Sumatra was closed against him, for the Dutch officials, aroused out of their customary lethargy, had seized his concession and had taken strong measures to prevent his return. Thus, with a crew composed of renegade Germans, Dutchmen, Malays and Chinese, he was compelled to keep to the limits of his submarine until his career of wanton destruction was brought to a close either by an act of God or the missiles of one of the avenging craft that were ever on the look-out to rid the seas of a scourge. Meantime Karl von Harburg was directing his attention to the Somali and Zanzibar coasts. Here he could, with little risk, replenish his stock of provisions, while he was within easy distance of the recognized tracks of vessels trading on the East coast of Africa. "So our sphere of operations is pretty well defined," remarked Captain Restronguet when the message was brought him. "It is not altogether to my liking, for I have some unpleasant recollections of the Somali coast. Not quite so bad as the West Coast, of course, but quite bad enough." "You have already visited this coast in the ’Aphrodite’?" asked the sub. "No; it was in a tramp steamer. We were trading, and instead of getting a profit for the owners we lost half our crew by fever and the bulk of our cargo was seized by the Arabs. That was some years ago. The fever is still there, and no doubt the predatory instincts of the Swahilis and Somalis are as strong as ever. But in a submarine things may be very different."