"The case seemed hopeless enough, although there were five of us after the thief. McFarlane was in London, and had been for a month, but Scotland Yard could give him no help, and the last I heard of him he was roaming through Surrey after a man with a white spot in his hair. Harrison had gone to Paris. He kept writing me that clews were plenty and the scent hot, but as Dennet, in Berlin, and Clancy, in Vienna, wrote me the same thing, I began to doubt these gentlemen's ability. "'You say,' I answered Harrison, 'that the fellow is a Frenchman, and that he is now concealed in Paris; but Dennet writes me by the same mail that the thief is undoubtedly a German, and was seen yesterday in Berlin. To-day I received a letter from Clancy, assuring me that Vienna holds the culprit, and that he is an Austrian from Trieste. Now, for Heaven's sake,' I ended, 'let me alone and stop writing me letters until you have something to write about.' "The night-clerk at the Waldorf had furnished us with our first clew. On the night of my aunt's death he had seen a tall, grave-faced man hurriedly leave the hotel. As the man passed the desk he removed his hat and mopped his forehead, and the night-clerk noticed that in the middle of his head there was a patch of hair as white as snow. "We worked this clew for all it was worth, and, a month later, I received a cable despatch from Paris, saying that a man answering to the description of the Waldorf suspect had offered an enormous crimson diamond for sale to a jeweller in the Palais Royal. Unfortunately the fellow took fright and disappeared before the jeweller could send for the police, and since that time McFarlane in London, Harrison in Paris, Dennet in Berlin, and Clancy in Vienna had been chasing men with white patches on their hair until no gray-headed patriarch in Europe was free from suspicion. I myself had sleuthed it through England, France, Holland, and Belgium, and now I found myself in Antwerp at the Hotel St. Antoine, without a clew that promised anything except another outrage on some respectable white-haired citizen. The case seemed hopeless enough, unless the thief tried again to sell the gem. Here was our only hope, for, unless he cut the stone into smaller ones, he had no more chance of selling it than he would have had if he had stolen the Venus of Milo and peddled her about the Rue de Seine. Even were he to cut up the stone, no respectable gem collector or jeweller would buy a crimson diamond without first notifying me; for although a few red stones are known to collectors, the color of the Crimson Diamond was absolutely unique, and there was little probability of an honest mistake.