“You must leave it as it is. I shall drop round early to-morrow morning and chat the matter over. It is possible that I may be in a position then to indicate some course of action. Meanwhile, you change nothing - nothing at all.”

“Very good, Mr. Holmes.”

“You can be perfectly easy in your mind. We shall certainly find some way out of your difficulties. I will take the black clay with me, also the pencil cuttings. Good-bye.”

When we were out in the darkness of the quadrangle, we again looked up at the windows. The Indian still paced his room. The others were invisible.

“Well, Watson, what do you think of it?” Holmes asked, as we came out into the main street. “Quite a little parlour game - sort of three-card trick, is it not? There are your three men. It must be one of them. You take your choice. Which is yours?”

“The foul-mouthed fellow at the top. He is the one with the worst record. And yet that Indian was a sly fellow also. Why should he be pacing his room all the time?”

“There is nothing in that. Many men do it when they are trying to learn anything by heart.”

“He looked at us in a queer way.”

“So would you, if a flock of strangers came in on you when you were preparing for an examination next day, and every moment was of value. No, I see nothing in that. Pencils, too, and knives - all was satisfactory. But that fellow does puzzle me.”

“Who?”

“Why, Bannister, the servant. What’s his game in the matter?”

“He impressed me as being a perfectly honest man.”

“So he did me. That’s the puzzling part. Why should a perfectly honest man - - Well, well, here’s a large stationer’s. We shall begin our researches here.”

There were only four stationers of any consequences in the town, and at each Holmes produced his pencil chips, and bid high for a duplicate. All were agreed that one could be ordered, but that it was not a usual size of pencil, and that it was seldom kept in stock. My friend did not appear to be depressed by his failure, but shrugged his shoulders in half-humorous resignation.

“No good, my dear Watson. This, the best and only final clue, has run to nothing. But, indeed, I have little doubt that we can build up a sufficient case without it. By Jove! my dear fellow, it is nearly nine, and the landlady babbled of green peas at seven-thirty. What with your eternal tobacco, Watson, and your irregularity at meals, I expect that you will get notice to quit, and that I shall share your downfall - not, however, before we have solved the problem of the nervous tutor, the careless servant, and the three enterprising students.”

Holmes made no further allusion to the matter that day, though he sat lost in thought for a long time after our belated dinner. At eight in the morning, he came into my room just as I finished my toilet.

“Well, Watson,” said he, “it is time we went down to St. Luke’s. Can you do without breakfast?”

“Certainly.”

“Soames will be in a dreadful fidget until we are able to tell him something positive.”

“Have you anything positive to tell him?”

“I think so.”

“You have formed a conclusion?”

“Yes, my dear Watson, I have solved the mystery.”

“But what fresh evidence could you have got?”

“Aha! It is not for nothing that I have turned myself out of bed at the untimely hour of six. I have put in two hours’ hard work and covered at least five miles, with something to show for it. Look at that!”

He held out his hand. On the palm were three little pyramids of black, doughy clay.

“Why, Holmes, you had only two yesterday.”