“Certainly, child, I do mean just that thing,” Mrs. Wilson said, laughing lightly.  “You need not take my request so seriously.  Mr. Hamlin will appreciate the joke more than any one else when I have explained it to him.  Won’t you keep your word and grant me this favor?”

“I can’t do what you ask, Mrs. Wilson,” Bab said slowly.  “I’m awfully sorry, but it wouldn’t be honorable.”

Mrs. Wilson turned away her head, so that Barbara could not see the expression of her face.  “Very well, Miss Thurston,” she said sharply.  “Don’t trouble about it, if you think you will be committing one of the cardinal sins in doing me this favor.  But don’t you think you are rather ungrateful?  You were perfectly willing to accept my offer the other day when you were in need of money to pay your sister’s debt, but now you are in no hurry to cancel your obligation.  I consider you an extremely disobliging young woman.”

Barbara sat silent and ashamed.  Yet she made no effort to propitiate her angry hostess.

The butler came to the library door to announce the arrival of Mr. Hamlin.

Barbara rose quickly.  “I am so sorry not to be able to do you the favor you asked of me, Mrs. Wilson,” she said in a low tone.

Mrs. Wilson did not reply.  Then in a flash Barbara Thurston remembered something!  It was the promise Marjorie Moore had asked of her, and which Ruth Stuart had insisted upon her making.  Without recalling that promise at the time, Bab had still kept her word.  She had been asked to do some one a favor—­and she had refused.  But of course Marjorie Moore must have had some other thing in mind when she made her curious demand.  Now that Barbara thought again of her vow, she determined to be wary for the rest of the evening and to keep as far away from Peter Dillon as possible.

“I am going to play chaperon at your house in the near future, Harriet,” Mrs. Wilson announced, as her guests were saying good night.  “Your father says he is to be out of town on business and that I may look after you.”

“We shall be delighted to have you, Mrs. Wilson,” Harriet returned politely, though she wondered why her father had suddenly requested Mrs. Wilson to act as chaperon.  Harriet had often stayed at home alone with only their faithful old servants to look after her, when her father went away for a short time.  And now that she had the four “Automobile Girls” as her guests, she did not feel in need of a chaperon.

Peter Dillon had not spoken to Bab again during the evening, but had studiously avoided her, and Bab was exceedingly glad that he had kept his distance.  But as she put on her coat to go home, she heard the rustle of a small piece of paper.

Barbara glanced down at it, of course, and found that some one had pinned a folded square of paper to the inner lining of her coat.

She blushed furiously, for fear one of the other guests would discover what had happened.  Bab hated sentimentality and secrecy more than anything in the world.  Inside the folded square of paper she found the tiny faded rose-bud, Peter Dillon had placed in his pocket that day when he had picked the two buds in the old Washington garden at Mt.  Vernon.