`So I think. But if we can only trace L. L. it should clear up the whole business. We have gained that much. We know that there is someone who has the facts if we can only find her. What do you think we should do?'

`Let Holmes know all about it at once. It will give him the clue for which he has been seeking. I am much mistaken if it does not bring him down.'

I went at once to my room and drew up my report of the morning's conversation for Holmes. It was evident to me that he had been very busy of late, for the notes which I had from Baker Street were few and short, with no comments upon the information which I had supplied and hardly any reference to my mission. No doubt his blackmailing case is absorbing all his faculties. And yet this new factor must surely arrest his attention and renew his interest. I wish that he were here.

October 17th. All day to-day the rain poured down, rustling on the ivy and dripping from the eaves. I thought of the convict out upon the bleak, cold, shelterless moor. Poor devil! Whatever his crimes, he has suffered something to atone for them. And then I thought of that other one - the face in the cab, the figure against the moon. Was he also out in that deluged - the unseen watcher, the man of darkness?

In the evening I put on my waterproof and I walked far upon the sodden moor, full of dark imaginings, the rain beating upon my face and the wind whistling about my ears. God help those who wander into the great mire now, for even the firm uplands are becoming a morass. I found the black tor upon which I had seen the solitary watcher, and from its craggy summit I looked out myself across the melancholy downs.

Rain squalls drifted across their russet face, and the heavy, slate-coloured clouds hung low over the landscape, trailing in gray wreaths down the sides of the fantastic hills. In the distant hollow on the left, half hidden by the mist, the two thin towers of Baskerville Hall rose above the trees. They were the only signs of human life which I could see, save only those prehistoric huts which lay thickly upon the slopes of the hills. Nowhere was there any trace of that lonely man whom I had seen on the same spot two nights before.

As I walked back I was overtaken by Dr. Mortimer driving in his dog-cart over a rough moorland track which led from the outlying farmhouse of Foulmire. He has been very attentive to us, and hardly a day has passed that he has not called at the Hall to see how we were getting on. He insisted upon my climbing into his dog-cart, and he gave me a lift homeward. I found him much troubled over the disappearance of his little spaniel. It had wandered on to the moor and had never come back. I gave him such consolation as I might, but I thought of the pony on the Grimpen Mire, and I do not fancy that he will see his little dog again.

`By the way, Mortimer,' said I as we jolted along the rough road, `I suppose there are few people living within driving distance of this whom you do not know?'

`Hardly any, I think.'

`Can you, then, tell me the name of any woman whose initials are L. L.?'

He thought for a few minutes.

`No,' said he. `There are a few gipsies and labouring folk for whom I can't answer, but among the farmers or gentry there is no one whose initials are those. Wait a bit though,' he added after a pause. `There is Laura Lyons - her initials are L. L. - but she lives in Coombe Tracey.'

`Who is she?' I asked.

`She is Frankland's daughter.'