He merely bowed to them, lit a second pipe and smoked it placidly, standing, in the corridor.

The train started. Ten minutes later, he came and sat down beside the countess and asked:

"Have you the ring on you, madame?"

"Yes."

"Please let me look at it."

He took it and examined it:

"As I thought: it is a faked diamond."

"Faked?"

"Yes, by a new process which consists in subjecting diamond-dust to enormous heat until it melts ... whereupon it is simply reformed into a single diamond."

"Why, but my diamond is real!"