Hamilton Gould’s big hand fell familiarly on the silver-haired individual’s shoulder.

“I think, sir,” he declared emphatically, “that to follow up a train of reasoning like that, to draw a conclusion with such clearness and precision, there’s only one man in all the world, above all only one American—and I think you are that man, Tom Bob in person!”

The man addressed smiled as he looked with sparkling eyes in the face of the genial globe-trotter.

“You are right,” he said simply, “I am Tom Bob.”

It was the signal for an outburst of enthusiasm and curiosity that soon spread to every passenger in the carriage. All crowded round the famous detective, each more eager than the other to speak to the great man.

“I beg and pray,” Mrs. Bigelow urged her husband, “you will introduce me; how delightful, how amusing to know a detective!”

But already Tom Bob, like the perfect man of the world he was, was paying his respects to the Princess Danidoff.

“We possess some good friends in common, Princess,” he was saying, “the Count and Countess Karenisky; I knew them well when I was staying at St. Petersburg; in fact, I had an opportunity of doing them a small service.”

“At the time of the Nihilists, was it not?” interrupted the Princess Sonia.

“Yes, indeed, during that critical period ...”