“Why, sir, if I chose not to answer, I should be within my rights and would tell you nothing ... But there, I have nothing to hide—I am a student, a medical student, sir.”

The young man was evidently annoyed and turning his back on his questioner, he left the corridor.

Suddenly, a few moments after this, the train was plunged into utter darkness. The track, after running for some distance alongside the Seine near Bonnières, had entered a tunnel. The Princess Danidoff’s anxious voice was heard complaining: “Why isn’t the carriage lighted? How very extraordinary!”

Tom Bob gave a sharp order:

“Have a care, ladies; look out, gentlemen; this darkness is altogether abnormal; it is due to no negligence on the part of the Company, but undoubtedly to the act of some miscreant; guard your jewelry, watch your pockets.”

A few moments that seemed like hours, and then, issuing suddenly from the bowels of the earth, the train regained the light of day and sped on across the open country.

Mrs. Bigelow gave a cry; her reticule had vanished. “My bag,” she groaned, “what has become of my little bag? Why, it’s appalling, verily this land of France is nothing but a den of thieves.”

Mr. Van Buren remarked: “I thought just now Mr. Bob was joking, but I am beginning to think he was perfectly serious.”

“By Gad!” exclaimed Ascott, who could not believe his pocket-book had really vanished and had just finished turning his portmanteau upside down, “by Gad! I think I ought to know something about it.”

The American detective was biting his lips with annoyance; mechanically he lit a cigarette, then tossed it away, only to light another.