Seating himself by the open window, he took out from his pocket the silken cord which Ferrara had dropped in the Museum, and examined it curiously. His examination of the thing did not serve to enlighten him respecting its character. It was merely a piece of silken cord, very closely and curiously plaited. He threw it down on the table, determined to show it to Dr. Cairn at the earliest opportunity. He was conscious of a sort of repugnance; and prompted by this, he carefully washed his hands as though the cord had been some unclean thing. Then, he sat down to work, only to realise immediately, that work was impossible until he had confided in somebody his encounter with Ferrara.
Lifting the telephone receiver, he called up Dr. Cairn, but his father was not at home.
He replaced the receiver, and sat staring vaguely at his open notebook.
For close upon an hour Robert Cairn sat at his writing-table, endeavouring to puzzle out a solution to the mystery of Ferrara's motive. His reflections served only to confuse his mind.
A tangible clue lay upon the table before him--the silken cord. But it was a clue of such a nature that, whatever deductions an expert detective might have based upon it, Robert Cairn could base none. Dusk was not far off, and he knew that his nerves were not what they had been before those events which had led to his Egyptian journey. He was back in his own chamber--scene of one gruesome outrage in Ferrara's unholy campaign; for darkness is the ally of crime, and it had always been in the darkness that Ferrara's activities had most fearfully manifested themselves.
Cairn ran to the window, and, leaning out, looked down into the court below. He could have sworn that a voice--a voice possessing a strange music, a husky music, wholly hateful--had called him by name. But at the moment the court was deserted, for it was already past the hour at which members of the legal fraternity desert their business premises to hasten homewards. Shadows were creeping under the quaint old archways; shadows were draping the ancient walls. And there was something in the aspect of the place which reminded him of a quadrangle at Oxford, across which, upon a certain fateful evening, he and another had watched the red light rising and falling in Antony Ferrara's rooms.