The girl, who was probably his _inamorata_, introduced them, whereupon he lifted his hat with his finger and thumb and swung it back upon his head with a twist--an action by which one Camorrist betrays his allegiance to the initiated. For a few moments they conversed together, then the girl, wishing the trio _buona sera_, sped away, and passing me was again lost in the darkness, while the men, walking together slowly, came on in my direction. The doctor was conversing with the young man in low whispers, and it seemed to me that he was giving him certain instructions. But I could not, of course, approach sufficiently near to overhear what was said. Miller was listening, but said nothing, except when addressed by his friend. Outside the massive Castel S. Angelo there is a cab-rank, and all three entered a closed cab. That there was some dark conspiracy in progress I could not doubt. The presence of that young swaggerer--a man capable of committing any crime I could see--was distinctly suspicious. Besides they dare not be seen with him; therefore they took a closed cab, the only one upon the rank on that hot night. They moved off across the bridge, and when they were a hundred yards away I got into one of the open cabs and told the driver to follow, for I was determined at all hazards to ascertain what cunning scheme was in progress. Fortunately, on account of my linen suit being dirty, I had exchanged it for one of dark blue serge, therefore I was not so conspicuous in the darkness as was Miller. To my surprise they drove direct to the railway station, where they alighted and the doctor went to take tickets. Noticing this, I told my driver to jump down and overhear their destination, promising him five francs for the information. In a moment he was gone, while I minded his horse. Five minutes later he returned, saying:-- "The Signore has taken three second-class tickets to Tivoli." Tivoli! What, I wondered, was their object in going out to Tivoli at that hour? I watched them pass the barrier on to the platform; then I myself took a ticket for the same destination, passed through, and entered an empty compartment of the waiting train. I saw, however, that while Miller and his friend were in a second-class carriage, the young man in the grey felt hat was in a third-class compartment. They were evidently taking precautions not to be seen in his company. I was sorely tempted to slip across to the police office and ask the _delegato_ to allow a detective to accompany me. Yet if I did this I should only be giving Miller into the hands of the police, and thus quite ruin all my chances of discovering the truth. No. If I wished to find out what was in progress I was, I saw, compelled to continue fearless and alone. Something desperate was in progress, otherwise they would never have sought the services of that young Camorrist. Miller was far too gentlemanly a rascal to associate with common criminals.