assigned for job next day advanced shine five hundred on account work on wellington serral matter repairs black machine fifty party apartment same night champagne one hundred fifty caterer one hundred tips fifty five to janitor taxis twelve must stir phil up on work for grimsby matter memorandum arrange for yacht mooring on east river instead of north after wednesday eighth job finis memorandum settle telephone exchange proceeds not later than monday paid electrician special wiring two hundred in full settlement.”

“There, Miss Helene, how do you like my little game of letter building?”

There was a boyish gleam of triumph in his smile as he turned toward her.

“You are a wizard, but how did you work it all out?” There was no smile in her face, only a mingled horror at the revelations of this calculating monster in his businesslike murder work, and an unfeigned admiration for Shirley’s keenness.

“A very old method, but one which would have availed for naught without your help.  The letter paper which you used and the unmistakable identity of Warren’s machine are two more bars of iron with which to imprison him.  The paper of that note is the same on which they wrote to Van Ceft for money, and their threats to me.  This shows from a microscopic examination of its texture.  I will give the whole book to a trustworthy stenographer:  more than six months of these little confessions are tabulated here.  Warren was evidently so used to this code that he could write in it as easily as I do with the straight alphabet.  His training in German universities developed a thoroughness, a methodical recording of every thing, which is apt to cost him dearly.  And his undoubted vanity prompted him to have a little volume of his own in that library to which he could turn occasionally for the retrospection of his own cleverness.  Now, I must investigate this clever telephone system.  I think I have the clue necessary.”

He intrusted the book to Helene for the morning, promising to return in an hour or two with new information, drolly refusing to tell her his destination.

“You’re a bad, bold boy, and should be spanked, for not letting some one know where to look for you in case you get into difficulties,” she pouted.  “Perhaps I will do some equally foolish thing myself.”

“If you knew how you frightened me yesterday!” he began.

“Did you really worry and really care?” But Shirley had slipped out of the door, leaving her to wonder, and then begin that long delayed letter to Jack.

CHAPTER XIX

AN EXPEDITION UNDERGROUND

The criminologist picked his way through the swarming vehicles which swung up and down Broadway, across to Seventh Avenue, where he turned into a plumber’s shop.  This fellow had handled small jobs on Shirley’s extensive real estate holdings, and he was naturally delighted to do a favor in the hope of obtaining new work.