Holmes grinned at the last item. “Well,” he said, “I say now, as I said then, that a man should keep his little brain-attic stocked with all the furniture that he is likely to use, and the rest he can put away in the lumber-room of his library, where he can get it if he wants it. Now, for such a case as the one which has been submitted to us to-night, we need certainly to muster all our resources. Kindly hand me down the letter K of the American Encyclopaedia which stands upon the shelf beside you. Thank you. Now let us consider the situation and see what may be deduced from it. In the first place, we may start with a strong presumption that Colonel Openshaw had some very strong reason for leaving America. Men at his time of life do not change all their habits and exchange willingly the charming climate of Florida for the lonely life of an English provincial town. His extreme love of solitude in England suggests the idea that he was in fear of someone or something, so we may assume as a working hypothesis that it was fear of someone or something which drove him from America. As to what it was he feared, we can only deduce that by considering the formidable letters which were received by himself and his successors. Did you remark the postmarks of those letters?”

“The first was from Pondicherry, the second from Dundee, and the third from London.”

“From East London. What do you deduce from that?”

“They are all seaports. That the writer was on board of a ship.”

“Excellent. We have already a clue. There can be no doubt that the probability - the strong probability - is that the writer was on board of a ship. And now let us consider another point. In the case of Pondicherry, seven weeks elapsed between the threat and its fulfillment, in Dundee it was only some three or four days. Does that suggest anything?”

“A greater distance to travel.”

“But the letter had also a greater distance to come.”

“Then I do not see the point.”

“There is at least a presumption that the vessel in which the man or men are is a sailing-ship. It looks as if they always sent their singular warning or token before them when starting upon their mission. You see how quickly the deed followed the sign when it came from Dundee. If they had come from Pondicherry in a steamer they would have arrived almost as soon as their letter. But, as a matter of fact, seven weeks elapsed. I think that those seven weeks represented the difference between the mail-boat which brought the letter and the sailing vessel which brought the writer.”

“It is possible.”

“More than that. It is probable. And now you see the deadly urgency of this new case, and why I urged young Openshaw to caution. The blow has always fallen at the end of the time which it would take the senders to travel the distance. But this one comes from London, and therefore we cannot count upon delay.”

“Good God!” I cried. “What can it mean, this relentless persecution?”

“The papers which Openshaw carried are obviously of vital importance to the person or persons in the sailing-ship. I think that it is quite clear that there must be more than one of them. A single man could not have carried out two deaths in such a way as to deceive a coroner’s jury. There must have been several in it, and they must have been men of resource and determination. Their papers they mean to have, be the holder of them who it may. In this way you see K. K. K. ceases to be the initials of an individual and becomes the badge of a society.”

“But of what society?”

“Have you never-” said Sherlock Holmes, bending forward and sinking his voice - “have you never heard of the Ku Klux Klan?”

“I never have.”

Holmes turned over the leaves of the book upon his knee. “Here it is,” said he presently: