1.  Love, family trouble.

2.  A romantic disposition.

3.  Temporary insanity, self-destruction.

4.  Criminal assault.

5.  Aphasia.

6.  Kidnapping.

“Those are the reasons why people disappear, eliminating criminals and those who have financial difficulties.  Dream on that and see if you can work out the answer in your subliminal consciousness.  Good-night.”

Needless to say, I was no further advanced in the morning than at midnight, but Kennedy seemed to have evolved at least a tentative programme.  It started with a visit to the public library, where he carefully went over the ground already gone over by the police.  Finding nothing, he concluded that Miss Gilbert had not found what she wanted at the library and had continued the quest, even as he was continuing the quest of herself.

His next step was to visit the department-store.  The purchase had been an inconsequential affair of half a dozen handkerchiefs, to be sent home.  This certainly did not look like a premeditated disappearance; but Craig was proceeding on the assumption that this purchase indicated nothing except that there had been a sale of handkerchiefs which had caught her eye.  Having stopped at the library first and a book-shop afterward, he assumed that she had also visited the book-department of the store.  But here again nobody seemed to recall her or that she had asked for anything in particular.

Our last hope was the book-shop.  We paused for a moment to look at the display in the window, but only for a moment, for Craig quickly pulled me along inside.  In the window was a display of books bearing the sign: 

BOOKS ON NEW THOUGHT, OCCULTISM, CLAIRVOYANCE, MESMERISM

Instead of attempting to go over the ground already traversed by the police, who had interrogated the numerous clerks without discovering which one, if any, had waited on Miss Gilbert, Kennedy asked at once to see the record of sales of the morning on which she had disappeared.  Running his eye quickly down the record, he picked out a work on clairvoyance and asked to see the young woman who had made the sale.  The clerk was, however, unable to recall to whom she had sold the book, though she finally admitted that she thought it might have been a young woman who had some difficulty in making up her mind just which one of the numerous volumes she wanted.  She could not say whether the picture Kennedy showed her of Miss Gilbert was that of her customer, nor was she sure that the customer was not escorted by some one.  Altogether it was nearly as hazy as our interview with Lawton.

“Still,” remarked Kennedy cheerfully, “it may furnish a clue, after all.  The clerk at least was not positive that it was not Miss Gilbert to whom she sold the book.  Since we are down in this neighbourhood, let us drop in and see Mr. Gilbert again.  Perhaps something may have happened since last night.”