Leaving our mysterious visitor in the charge of Mrs. Pearson, we drove away, and duly caught the train by the skin of our teeth. Poirot was alternately silent and loquacious. He would sit staring out of the window like a man lost in a dream, apparently not hearing a word that I said to him. Then, reverting to animation suddenly, he would shower injunctions and commands upon me, and urge the necessity of constant marconigrams.

We had a long fit of silence just after we passed Woking. The train, of course, did not stop anywhere until Southampton; but just here it happened to be held up by a signal.

“Ah! Sacré mille tonnerres! ” cried Poirot suddenly. “But I have been an imbecile. I see clearly at last. It is undoubtedly the blessed saints who stopped the train. Jump, Hastings, but jump, I tell you.”

In an instant he had unfastened the carriage door, and jumped out on the line.