Jim Frobisher moved carefully round on the outskirts of the room, taking care not to alter the disarrangements of the furniture. He looked the bottles over. Not one of them held a drop of that pale lemon-coloured solution which the Professor, in his Treatise, had described. Hanaud shut and locked the doors of the cabinet again and stepped carefully over to the bureau. It stood open, and a few papers were strewn upon the flap. He sat down at the bureau and began carefully to search it. Jim sat down in a chair. Somehow it had leaked out that, since this morning, Hanaud knew of Jean Cladel. Jean Cladel therefore must be stopped from any revelations; and he had been stopped. Frobisher could no longer doubt that murder had been done on the night of April the 27th, in the Maison Crenelle. Development followed too logically upon development. The case was building itself up—another storey had been added to the edifice with this new crime. Yes, certainly and solidly it was building itself up—this case against some one.
CHAPTER EIGHTEEN: The White Tablet
Within the minute that case was to be immeasurably strengthened. An exclamation broke from Hanaud. He sprang to his feet and turned on the light of a green-shaded reading lamp, which stood upon the ledge of the bureau. He was holding now under the light a small drawer, which he had removed from the front of the bureau. Very gingerly he lifted some little thing out of it, something that looked like a badge that men wear in their buttonholes. He laid it down upon the blotting paper; and in that room of death laughed harshly.
He beckoned to Jim.
"Come and look!"
What Jim saw was a thin, small, barbed iron dart, with an iron stem. He had no need to ask its nature, for he had seen its likeness that morning in the Treatise of the Edinburgh Professor. This was the actual head of Simon Harlowe's poison-arrow.
"You have found it!" said Jim in a voice that shook.
"Yes."
Hanaud gave it a little push, and said thoughtfully: