With her pretty lips set in a resolute line she left the house and walked rapidly north.  Come what may she would go on with it.  Her country needed her, and that was all-sufficient.

CHAPTER VI

THE MISSING MESSAGE

After Jane left Carter at the drug-store, he did not cross immediately to the bookshop opposite.  His detective work was not of that sort.  He strolled leisurely around the corner long enough to give some directions to his two aides waiting there and then, moving across the street, paused in front of the window of books as if something there had attracted his attention.  All the while he was keeping a sharp eye for any person who looked as if they might be connected in any way with old Hoff.  Satisfied that his entrance was unobserved he strolled casually in and began looking over the volumes in the lending library.  The lone clerk in the store—­a young woman—­at first volunteered some suggestions, but as they went unheeded she returned to her work of posting up the accounts.

As soon as her attention was occupied Carter moved at once to the end of the shelf that Miss Strong had indicated and removed the fifth book.  To his amazement he found nothing whatever concealed between the leaves.  The books on either side on the same shelf failed to yield up anything.  He tried the shelf above and the shelf below.  Perhaps Miss Strong had been mistaken in the directions.  He examined the books at the other end.  There was nothing there.  He recalled that the girl had said that no one except two girls had entered the store between the time she had discovered and copied the cipher and the time of his arrival.  If these girls had not taken the message away there could be only one other explanation—­the clerk in the bookstore must have removed it and concealed it somewhere.

“Which of the war books do you think the best?” he asked for the purpose of starting a conversation.

“There’s that many it is hard to say, sir,” the young woman answered.

Something in her inflection made him look sharply at her.  Her accent surely was English, or possibly Canadian.  A few judicious questions quickly brought out the information that she came from Liverpool and that she had three brothers in the British army.  Carter decided that it was preposterous to suspect her of being in league with German agents.  There was only one other thing that could have happened.  Some one else—­some one who had eluded Miss Strong’s notice—­had removed the cipher message.

Promptly he had telephoned to her to meet him.  He was glad that he had done so, for her evident perturbation as she answered the ’phone both interested and puzzled him.  Pausing just long enough to report to Chief Fleck, he hastened to the rendezvous, arriving there first.  He selected a bench apart from the others, where the wall jutted out from the walk, and seating himself, idled there as if merely watching the river.  In obedience with his instructions Jane, when she arrived, planted herself nonchalantly on the same bench, and paying no attention to him, pretended to be reading a letter.