“My dear fellow, you have been invaluable to me in this as in many other cases, and I beg that you will forgive me if I have seemed to play a trick upon you. In truth, it was partly for your own sake that I did it, and it was my appreciation of the danger which you ran which led me to come down and examine the matter for myself. Had I been with Sir Henry and you it is confident that my point of view would have been the same as yours, and my presence would have warned our very formidable opponents to be on their guard. As it is, I have been able to get about as I could not possibly have done had I been living in the Hall, and I remain an unknown factor in the business, ready to throw in all my weight at a critical moment.”

“But why keep me in the dark?”

“For you to know could not have helped us and might possibly have led to my discovery. You would have wished to tell me something, or in your kindness you would have brought me out some comfort or other, and so an unnecessary risk would be run. I brought Cartwright down with me - you remember the little chap at the express office - and he has seen after my simple wants: a loaf of bread and a clean collar. What does man want more? He has given me an extra pair of eyes upon a very active pair of feet, and both have been invaluable.”

“Then my reports have all been wasted!” - My voice trembled as I recalled the pains and the pride with which I had composed them.

Holmes took a bundle of papers from his pocket.

“Here are your reports, my dear fellow, and very well thumbed, I assure you. I made excellent arrangements, and they are only delayed one day upon their way. I must compliment you exceedingly upon the zeal and the intelligence which you have shown over an extraordinarily difficult case.”

I was still rather raw over the deception which had been practised upon me, but the warmth of Holmes’s praise drove my anger from my mind. I felt also in my heart that he was right in what he said and that it was really best for our purpose that I should not have known that he was upon the moor.

“That’s better,” said he, seeing the shadow rise from my face. “And now tell me the result of your visit to Mrs. Laura Lyons - it was not difficult for me to guess that it was to see her that you had gone, for I am already aware that she is the one person in Coombe Tracey who might be of service to us in the matter. In fact, if you had not gone to-day it is exceedingly probable that I should have gone to-morrow.”

The sun had set and dusk was settling over the moor. The air had turned chill and we withdrew into the hut for warmth. There, sitting together in the twilight, I told Holmes of my conversation with the lady. So interested was he that I had to repeat some of it twice before he was satisfied.

“This is most important,” said he when I had concluded. “It fills up a gap which I had been unable to bridge in this most complex affair. You are aware, perhaps, that a close intimacy exists between this lady and the man Stapleton?”

“I did not know of a close intimacy.”

“There can be no doubt about the matter. They meet, they write, there is a complete understanding between them. Now, this puts a very powerful weapon into our hands. If I could only use it to detach his wife- -”

“His wife?”

“I am giving you some information now, in return for all that you have given me. The lady who has passed here as Miss Stapleton is in reality his wife.”

“Good heavens, Holmes! Are you sure of what you say? How could he have permitted Sir Henry to fall in love with her?”

“Sir Henry’s falling in love could do no harm to anyone except Sir Henry. He took particular care that Sir Henry did not make love to her, as you have yourself observed. I repeat that the lady is his wife and not his sister.”