Frank Tristram, remarking that she would find London very different to Florence, raised his hand to his throat to loosen his collar, and in doing so displayed something which had until that moment remained concealed. A narrow ribbon was hidden beneath his large French cravat of black silk tied in a bow. The colour was royal blue, and from it was suspended the British royal arms, surmounted by the crown, with a silver greyhound pendant, the badge known on every railway from Calais to Ekaterinbourg, and from Stockholm to Reggio, as that of a King's Foreign Service Messenger. Captain Frank Tristram was one of the dozen wanderers on the face of the earth whose swift journeys and promptness in delivering despatches have earned for them the title of "The Greyhounds of Europe." So engrossed was the dark-haired girl in contemplating her strange surroundings that she scarcely uttered a word as the cab sped on swiftly through the deepening twilight across Trafalgar Square, along Pall Mall, and up the Haymarket. Suddenly, however, the blaze of electricity outside the Criterion brought to Frank Tristram's mind cherished recollections of whisky and soda, and, being thirsty after the journey, he shouted to the man to pull up there. "You, too, must be thirsty," he said, turning to her. "At this cafe, I think, they keep some of your Italian drinks--vermouth, menthe, or muscato." "Thank you--no," she replied, smiling sweetly. "The cup of English tea I had at Dover did me good, and I'm really not thirsty. You go and get something. I'll remain here." "Very well," he said. "I won't be more than a minute;" and as the cab drew up close to the door of the bar, he sprang out and entered the long saloon. His subsequent movements were, however, somewhat curious. After walking to the further end of the bar, he ordered a drink, idled over it for some minutes, his eyes glancing furtively at the lights of the cab outside. Suddenly, when he had uttered a few words to a passing acquaintance, he saw the vehicle move slowly on, probably under orders from the police; and the instant he had satisfied himself that neither Vittorina nor the cabman could observe him, he drained his glass, threw down a shilling, and without waiting for the change turned and continued through the bar, making a rapid exit by the rear door leading into Jermyn Street. As he emerged, a hansom was passing, and, hailing it, he sprang in, shouted an address, and drove rapidly away. Meanwhile the cabman who had driven him from Charing Cross sat upon his box patiently awaiting his return, now and then hailing the plethoric drivers of passing vehicles with sarcasm, as cab and 'bus drivers are wont to do, until fully twenty minutes had elapsed. Then, there being no sign of the reappearance of his fare, he opened the trap-door in the roof, exclaiming-- "Nice evenin' miss." There was no response. The man peered down eagerly for a moment in surprise then cried aloud--