Frobisher drew a long breath and lit a cigarette, and gave another proof that he was a very novice of a bull.
"What a mad thing to put the head of that arrow-shaft, which a glance at the plates in the Treatise would enable a child to identify, into an open tray of pens without the slightest concealment!" he exclaimed.
It looked as if Ann Upcott was wilfully pushing her neck into the wooden ring of the guillotine.
Hanaud shook his head.
"Not so mad, my friend! The old rules are the best. Hide a thing in some out-of-the-way corner, and it will surely be found. Put it to lie carelessly under every one's nose and no one will see it at all. No, no! This was cleverly done. Who could have foreseen that instead of looking on at our search you were going to plump yourself down in a chair and write your memorandum so valuable on Mademoiselle Ann's notepaper? And even then you did not notice your pen. Why should you?"
Jim, however, was not satisfied.
"It is a fortnight since Mrs. Harlowe was murdered, if she was murdered," he cried. "What I don't understand is why the arrow wasn't destroyed altogether!"
"But until this morning there was never any question of the arrow," Hanaud returned. "It was a curiosity, an item in a collection—why should one trouble to destroy it? But this morning the arrow becomes a dangerous thing to possess. So it must be hidden away in a hurry. For there is not much time. An hour whilst you and I admired Mont Blanc from the top of the Terrace Tower."
"And while Betty was out of the house," Jim added quickly.
"Yes—that is true," said Hanaud. "I had not thought of it. You can add that point, Monsieur Frobisher, to the reasons which put Mademoiselle Harlowe out of our considerations. Yes."