"I was in the Park, sir, with Annie—one of the housemaids, sir, and she pointed out the master to me walking with a foreign lady."
Again Poirot nodded.
"Now listen, Mason, this man whom you saw in the carriage talking to your mistress at the Gare de Lyon, how do you know it was not your master?"
"The master, sir? Oh, I don't think it could have been."
"But you are not sure," Poirot persisted.
"Well—I never thought of it, sir."
Mason was clearly upset at the idea.
"You have heard that your master was also on the train. What more natural than that it should be he who came along the corridor."
"But the gentleman who was talking to the mistress must have come from outside, sir. He was dressed for the street. In an overcoat and soft hat."
"Just so, Mademoiselle, but reflect a minute. The train has just arrived at the Gare de Lyon. Many of the passengers promenade themselves upon the quay. Your mistress was about to do so, and for that purpose had doubtless put on her fur coat, eh?"