“On entering the house, however, I examined, as you remember, the sill and framework of the hall window with my lens, and I could at once see that someone had passed out. I could distinguish the outline of an instep where the wet foot had been placed in coming in. I was then beginning to be able to form an opinion as to what had occurred. A man had waited outside the window; someone had brought the gems; the deed had been overseen by your son; he had pursued the thief; had struggled with him; they had each tugged at the coronet, their united strength causing injuries which neither alone could have effected. He had returned with the prize, but had left a fragment in the grasp of his opponent. So far I was clear. The question now was, who was the man and who was it brought him the coronet?

“It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. Now, I knew that it was not you who had brought it down, so there only remained your niece and the maids. But if it were the maids, why should your son allow himself to be accused in their place? There could be no possible reason. As he loved his cousin, however, there was an excellent explanation why he should retain her secret -the more so as the secret was a disgraceful one. When I remembered that you had seen her at that window, and how she had fainted on seeing the coronet again, my conjecture became a certainty.

“And who could it be who was her confederate? A lover evidently, for who else could outweigh the love and gratitude which she must feel to you? I knew that you went out little, and that your circle of friends was a very limited one. But among them was Sir George Burnwell. I had heard of him before as being a man of evil reputation among women. It must have been he who wore those boots and retained the missing gems. Even though he knew that Arthur had discovered him, he might still flatter himself that he was safe, for the lad could not say a word without compromising his own family.

“Well, your own good sense will suggest what measures I took next. I went in the shape of a loafer to Sir George’s house, managed to pick up an acquaintance with his valet, learned that his master had cut his head the night before, and, finally, at the expense of six shillings, made all sure by buying a pair of his cast-off shoes. With these I journeyed down to Streatham and saw that they exactly fitted the tracks.”

“I saw an ill-dressed vagabond in the lane yesterday evening,” said Mr. Holder.

“Precisely. It was I. I found that I had my man, so I came home and changed my clothes. It was a delicate part which I had to play then, for I saw that a prosecution must be avoided to avert scandal, and I knew that so astute a villain would see that our hands were tied in the matter. I went and saw him. At first, of course, he denied everything. But when I gave him every particular that had occurred, he tried to bluster and took down a life-preserver from the wall. I knew my man, however, and I clapped a pistol to his head before he could strike. Then he became a little more reasonable. I told him that we would give him a price for the stones he held - £1000 apiece. That brought out the first signs of grief that he had shown. ‘Why, dash it all!’ said he, ‘I’ve let them go at six hundred for the three!’ I soon managed to get the address of the receiver who had them, on promising him that there would be no prosecution. Off I set to him, and after much chaffering I got our stones at £1000 apiece. Then I looked in upon your son, told him that all was right, and eventually got to my bed about two o’clock, after what I may call a really hard day’s work.”