“Perhaps,” answered Monty, “but the uncertainty does allure me.  I always enjoyed skating on thin ice, from the days of college when I loved to get through a course of lectures on as little work as possible.  The satisfaction of ‘getting away with it’ against odds was so exhilarating.  I will return after my little dinner with Warren at the Club.  Where will you dine?”

“Your friend Dick Holloway is taking me to some restaurant where singing and music may alter my refusal to him.”

“Your refusal?” and Shirley shot a quick glance at the girl.  Her dimples appeared as she added:  “Yes—­he wants me to star in a little play for the coming spring, but I have had such fun playing in real-life drama that I said him nay.”

“Oh,” was all the criminologist said, but as he left, Helene’s laugh interpretated a little feminine satisfaction.  Monty’s mind was just disturbed enough about the attitude of Dick Holloway to keep him from worrying over the Warren case until he had reached the East River, near the yacht club mooring.

There was the white yacht which had been mentioned in the purloined book.  It was a trim, speedy craft.  The criminologist walked down a few blocks to the office of a boat contractor with whom he had dealt on bygone occasions.

“I want to engage a fast motor-boat, Mr. Manby,” was his request.  “The speediest thing you’ve got.  Keep it down at your dock, at Twenty-first Street, with plenty of gasoline and a man on duty all the time, starting with six o’clock to-night.  I may need it at a minute’s notice.”

“I’ve got a hydroplane which I’ll sell this spring to some yachtsman,” said Manby.  “It’s a bargain—­you can do forty miles an hour in it, without getting a drop of spray.  Shall I show it to you?”

“Yes, and the two men who you will have alternating on duty, so they will know me when I come for it.  I’ll pay for every minute it is reserved.”

They soon came to terms; the men were introduced and Shirley was well satisfied with the racing craft, which was moored according to his directions, handy for a quick embarkation.

Then he went up to the Holland Agency.  Cronin was disappointed in his results with the telephone confederate.  All of Warren’s men were close-mouthed, as though through some biting fear of swift and unerring vengeance for “squealing.”  Even the prisoners in the station-house had not volunteered to communicate with friends, as they were allowed to do by law.  They were “standing pat,” as the old detective declared in disgust.

“That proves one thing,” remarked the criminologist.  “They are not local products, or they would have friends other than their chief on whom to call for bail or aid.  Their whole work centers on him.  I think I will send a code message to this man Phil this afternoon or evening.  He may be able to read it, and if he does, it may assist us.  I wish you would have a man call on Miss Marigold at the California Hotel, so that she may know his face.  Then keep him covering her for they are apt to get suspicious of her and try to quiet her.  She is a game and fearless girl, but she is no match for this gang.”