Hansen nodded and strolled casually to the rear of the shop. The back door was clearly visible to our view, through a vista of antique furniture and tarnished hangings strung up for exhibition. We had followed the Scorpion--if he it was--so closely that I did not believe he would have had time to traverse the full length of the shop and make his exit without our having seen him as we came in. For our eyes had been on the rear door ever since we had entered. Gordon and I browsed around casually among the curios, handling and discussing some of them but I have no idea as to their nature. The Levantine had seated himself cross-legged on a Moorish mat close to the center of the shop and apparently took only a polite interest in our explorations. After a time Gordon whispered to me: "There is no advantage in keeping up this pretense. We have looked everywhere the Scorpion might be hiding, in the ordinary manner. I will make known my identity and authority and we will search the entire building openly." Even as he spoke a truck drew up outside the door and two burly negroes entered. The Levantine seemed to have expected them, for he merely waved them toward the back of the shop and they responded with a grunt of understanding. Gordon and I watched them closely as they made their way to a large mummy-case which stood upright against the wall not far from the back. They lowered this to a level position and then started for the door, carrying it carefully between them. "Halt!" Gordon stepped forward, raising his hand authoritatively. [Illustration: "Halt!" Gordon stepped forward, raising his hand authoritatively.] "I represent Scotland Yard," he said swiftly, "and have sanction for anything I choose to do. Set that mummy down; nothing leaves this shop until we have thoroughly searched it." The negroes obeyed without a word and my friend turned to the Levantine, who, apparently not perturbed or even interested, sat smoking a Turkish water-pipe. "Who was that tall man who entered just before we did, and where did he go?" "No one entered before you, sir. Or, if anyone did, I was at the back of the shop and did not see him. You are certainly at liberty to search my shop, sir." And search it we did, with the combined craft of a secret service expert and a denizen of the underworld--while Hansen stood stolidly at his post, the two negroes standing over the carved mummy-case watched us impassively and the Levantine sitting like a sphinx on his mat, puffing a fog of smoke into the air. The whole thing had a distinct effect of unreality.