The door opened after a discreet tap from the waiter and the lavish dinner which Craig had ordered appeared.  The door stayed open for a moment as the bus boy carried in the dishes.  A rustle of skirts and low musical laughter was wafted in to us and we caught a glimpse of another gay party passing down the hall.

“How many private dining-rooms are there?” asked Craig of the waiter.

“Just this one, sir, and the next one, which is smaller,” replied the model waiter, with the air of one who could be blind and deaf and dumb if he chose.

“Oh, then we were lucky to get this.”

“Yes, sir.  It is really best to telephone first to Julius to make sure and have one of the rooms reserved, sir.”

Craig made a mental note of the information.  The party in the next room were hilariously ordering, mostly from the wine list.  None of us had recognized any of them, nor had they paid much attention to us.

Craig had eaten little, although the food was very good.

“It’s a shame to come here and not see the whole place,” he remarked.  “I wonder if you would excuse me while I drop downstairs to look over things there—­perhaps ingratiate myself with that Titian?  Tell Miss Kendall about our visit to Langhorne’s office while I am gone, Walter.”

There was not much that I could tell except the bare facts, but I thought that Miss Kendall seemed especially interested in the broker’s reticence about his stenographer.

I had scarcely finished when Craig returned.  A glance at his face told me that even in this brief time something had happened.

“Did you meet the Titian?” I asked.

“Yes.  She is the stenographer and sometimes works the switchboard of the telephone.  I happened to strike the office while the clerk was at dinner and she was alone.  While I was talking to her I was looking about and my eye happened to fall on one of the letter boxes back of the desk, marked ‘Dr. Harris.’  Well, at once I had an overwhelming desire to get a note which I saw sticking in it.  So I called up a telephone number, just as a blind, and while she was at the switchboard I slipped the note into my pocket.  Here it is.”

He had laid an envelope down before us.  It was in a woman’s hand, written hastily.

“I’d like to know what was in it without Dr. Harris knowing it,” he remarked.  “Now, the secret service agents abroad have raised letter-opening to a fine art.  Some kinds of paper can be steamed open without leaving a trace, and then they follow that simple operation by reburnishing the flap with a bone instrument.  But that won’t do.  It might make this ink run.”

Among the ornaments were several with flat wooden bases.  Kennedy took one and placed it on the edge of the table, which was perfectly square.  Then he placed the envelope between the table and the base.

“When other methods fail,” he went on, “they place the envelope between two pieces of wood with the edges projecting about a thirty-second of an inch.”