"I don't understand at all," muttered Sime, "but as I presume you have a good reason for what you do, let it be as you propose. Can you give me any idea respecting what we may hope to find inside this place? I only entered once, and I am not anxious to repeat the experiment. The air is unbreathable, the descent to the level passage below is stiff work, and, apart from the inconvenience of navigating the latter passage, which as you probably know is only sixteen inches high, the climb up the vertical shaft into the tomb is not a particularly safe one. I exclude the possibility of snakes," he added ironically. "You have also omitted the possibility of Antony Ferrara," said Dr. Cairn. "Pardon my scepticism, doctor, but I cannot imagine any man voluntarily remaining in that awful place." "Yet I am greatly mistaken if he is not there!" "Then he is trapped!" said Sime grimly, examining a Browning pistol which he carried. "Unless--" He stopped, and an expression, almost of fear, crept over his stoical features. "That sixteen-inch passage," he muttered--"with Antony Ferrara at the further end!" "Exactly!" said Dr. Cairn. "But I consider it my duty to the world to proceed. I warn you that you are about to face the greatest peril, probably, which you will ever be called upon to encounter. I do not ask you to do this. I am quite prepared to go alone." "That remark was wholly unnecessary, doctor," said Sime rather truculently. "Suppose the other two proceed to their post." "But, sir--" began Robert Cairn. "You know the way," said the doctor, with an air of finality. "There is not a moment to waste, and although I fear that we are too late, it is just possible we may be in time to prevent a dreadful crime." The tall Egyptian and Robert Cairn went stumbling off amongst the heaps of rubbish and broken masonry, until an angle of the great wall concealed them from view. Then the two who remained continued the climb yet higher, following the narrow, zigzag path leading up to the entrance of the descending passage. Immediately under the square black hole they stood and glanced at one another. "We may as well leave our outer garments here," said Sime. "I note that you wear rubber-soled shoes, but I shall remove my boots, as otherwise I should be unable to obtain any foothold." Dr. Cairn nodded, and without more ado proceeded to strip off his coat, an example which was followed by Sime. It was as he stooped and placed his hat upon the little bundle of clothes at his feet that Dr. Cairn detected something which caused him to stoop yet lower and to peer at that dark object on the ground with a strange intentness. "What is it?" jerked Sime, glancing back at him. Dr. Cairn, from a hip pocket, took out an electric lamp, and directed the white ray upon something lying on the splintered fragments of granite. It was a bat, a fairly large one, and a clot of blood marked the place where its head had been. For the bat was decapitated!