“Then it amounts to this, Mr. Soames:  that, unless the Indian student recognized the roll as being proofs, the man who tampered with them came upon them accidentally without knowing that they were there.”

“So it seems to me.”

Holmes gave an enigmatic smile.

“Well,” said he, “let us go round.  Not one of your cases,
Watson—­mental, not physical.  All right; come if you want to.  Now, Mr.
Soames—­at your disposal!”

The sitting-room of our client opened by a long, low, latticed window on to the ancient lichen-tinted court of the old college.  A Gothic arched door led to a worn stone staircase.  On the ground floor was the tutor’s room.  Above were three students, one on each story.  It was already twilight when we reached the scene of our problem.  Holmes halted and looked earnestly at the window.  Then he approached it, and, standing on tiptoe with his neck craned, he looked into the room.

“He must have entered through the door.  There is no opening except the one pane,” said our learned guide.

“Dear me!” said Holmes, and he smiled in a singular way as he glanced at our companion.  “Well, if there is nothing to be learned here, we had best go inside.”

The lecturer unlocked the outer door and ushered us into his room.  We stood at the entrance while Holmes made an examination of the carpet.

“I am afraid there are no signs here,” said he.  “One could hardly hope for any upon so dry a day.  Your servant seems to have quite recovered.  You left him in a chair, you say.  Which chair?”

“By the window there.”

“I see.  Near this little table.  You can come in now.  I have finished with the carpet.  Let us take the little table first.  Of course, what has happened is very clear.  The man entered and took the papers, sheet by sheet, from the central table.  He carried them over to the window table, because from there he could see if you came across the courtyard, and so could effect an escape.”

“As a matter of fact, he could not,” said Soames, “for I entered by the side door.”

“Ah, that’s good!  Well, anyhow, that was in his mind.  Let me see the three strips.  No finger impressions—­no!  Well, he carried over this one first, and he copied it.  How long would it take him to do that, using every possible contraction?  A quarter of an hour, not less.  Then he tossed it down and seized the next.  He was in the midst of that when your return caused him to make a very hurried retreat—­very hurried, since he had not time to replace the papers which would tell you that he had been there.  You were not aware of any hurrying feet on the stair as you entered the outer door?”

“No, I can’t say I was.”

“Well, he wrote so furiously that he broke his pencil, and had, as you observe, to sharpen it again.  This is of interest, Watson.  The pencil was not an ordinary one.  It was above the usual size, with a soft lead, the outer colour was dark blue, the maker’s name was printed in silver lettering, and the piece remaining is only about an inch and a half long.  Look for such a pencil, Mr. Soames, and you have got your man.  When I add that he possesses a large and very blunt knife, you have an additional aid.”