Robert Cairn unwrapped the little parcel. It contained a penknife, the ivory handle charred as if it had been in a furnace. It was his own--which he had handed to his father in that awful cellar at the moment when the first spider had dropped; and a card was enclosed, bearing the pencilled words, "With Antony Ferrara's Compliments." CHAPTER XVII THE STORY OF ALI MOHAMMED Saluting each of the three in turn, the tall Egyptian passed from Dr. Cairn's room. Upon his exit followed a brief but electric silence. Dr. Cairn's face was very stern and Sime, with his hands locked behind him, stood staring out of the window into the palmy garden of the hotel. Robert Cairn looked from one to the other excitedly. "What did he say, sir?" he cried, addressing his father. "It had something to do with--" Dr. Cairn turned. Sime did not move. "It had something to do with the matter which has brought me to Cairo," replied the former--"yes." "You see," said Robert, "my knowledge of Arabic is _nil_--" Sime turned in his heavy fashion, and directed a dull gaze upon the last speaker. "Ali Mohammed," he explained slowly, "who has just left, had come down from the Fayum to report a singular matter. He was unaware of its real importance, but it was sufficiently unusual to disturb him, and Ali Mohammed es-Suefi is not easily disturbed." Dr. Cairn dropped into an armchair, nodding towards Sime. "Tell him all that we have heard," he said. "We stand together in this affair." "Well," continued Sime, in his deliberate fashion, "when we struck our camp beside the Pyramid of Meydum, Ali Mohammed remained behind with a gang of workmen to finish off some comparatively unimportant work. He is an unemotional person. Fear is alien to his composition; it has no meaning for him. But last night something occurred at the camp--or what remained of the camp--which seems to have shaken even Ali Mohammed's iron nerve." Robert Cairn nodded, watching the speaker intently. "The entrance to the Meydum Pyramid--," continued Sime. "_One_ of the entrances," interrupted Dr. Cairn, smiling slightly. "There is only one entrance," said Sime dogmatically. Dr. Cairn waved his hand. "Go ahead," he said. "We can discuss these archaeological details later." Sime stared dully, but, without further comment, resumed: