He executed the commission without a hitch. He called upon the German and introduced himself in low tones as a loyal subject of the Kaiser and asked to be taken into the house. There he presented his letter. When the German read it, he broke into a hearty laugh and said the password no longer really applied, because it referred to the coal pile. He had found, on account of the coal shortage, that at times he could not keep enough coal in the cellar to keep the suitcase covered, and that consequently he had had to conceal it elsewhere in the house. The caller joined him in laughter at this piece of humour, and the German excused himself and soon returned with the suitcase. It was not till several days later that he had the slightest inkling that the man he had entertained was an operative of the American Government. The plot for which Dr. Scheele was brought to earth was only a detail in the vast scheme of Germany’s treachery, but it was one of the most dastardly and most dramatic of those details, and its detection and unravelling revealed the men at the head of the German system in this country and their mutual relationships. In a previous chapter I have told something of the career of Franz von Rintelen. At this point he appears as an agent of Germany seeking to destroy the ships bearing American supplies to the Allies. One day Dr. Scheele received a caller, Eno Bode, a captain in the service of the North German Lloyd Steamship Company. Bode bore a card from Von Papen, ordering Scheele to execute any orders which Bode gave. Von Papen’s orders, in their turn, had come through Rintelen. Bode now disclosed to Dr. Scheele a most infernal plan. He was instructed to invent a bomb of simple mechanism, which could be placed in a ship’s cargo or its coal and which would not explode, but set fire to anything inflammable with which it came in contact. It must be devised to operate at any predetermined time after it was placed on board. To Dr. Scheele, a great chemist himself and possessed of every secret of the greatest nation of chemists in the world, this was a simple order. In his instructions he was forbidden to apply for his materials to any American concern through which the purchase might ever be traced. Consequently, he asked for technical assistance and was referred to Captain Carl Schmidt, the chief engineer of the _Friedrich der Grosse_, one of the great German liners interned at Hoboken. Schmidt placed at his disposal Charles Becker, the electrician of the _Friedrich der Grosse_. From him he obtained sections of lead pipe and thin sheets of lead and tin. The chemicals were easily obtained from strictly German sources.