On the other hand, it seemed an unthinkable coincidence that a man should dare to enter the room, and that by chance on that very day the papers were on the table. I dismissed that. The man who entered knew that the papers were there. How did he know?

“When I approached your room I examined the window. You amused me by supposing that I was contemplating the possibility of someone having in broad daylight, under the eyes of all these opposite rooms, forced himself through it. Such an idea was absurd. I was measuring how tall a man would need to be in order to see as he passed what papers were on the central table. I am six feet high, and I could do it with an effort. No one less than that would have a chance. Already you see I had reason to think that if one of your three students was a man of unusual height he was the most worth watching of the three.

“I entered and I took you into my confidence as to the suggestions of the side table. Of the centre table I could make nothing, until in your description of Gilchrist you mentioned that he was a long-distance jumper. Then the whole thing came to me in an instant, and I only needed certain corroborative proofs, which I speedily obtained.

“What happened was this. This young fellow had employed his afternoon at the athletic grounds, where he had been practising the jump. He returned carrying his jumping shoes, which are provided, as you are aware, with several sharp spikes. As he passed your window he saw, by means of his great height, these proofs upon your table, and conjectured what they were. No harm would have been done had it not been that as he passed your door he perceived the key which had been left by the carelessness of your servant. A sudden impulse came over him to enter and see if they were indeed the proofs. It was not a dangerous exploit, for he could always pretend that he had simply looked in to ask a question.

“Well, when he saw that they were indeed the proofs, it was then that he yielded to temptation. He put his shoes on the table. What was it you put on that chair near the window?”

“Gloves,” said the young man.

Holmes looked triumphantly at Bannister. “He put his gloves on the chair, and he took the proofs, sheet by sheet, to copy them. He thought the tutor must return by the main gate, and that he would see him. As we know, he came back by the side gate. Suddenly he heard him at the very door. There was no possible escape. He forgot his gloves, but he caught up his shoes and darted into the bedroom. You observe that the scratch on that table is slight at one side, but deepens in the direction of the bedroom door. That in itself is enough to show us that the shoe had been drawn in that direction and that the culprit had taken refuge there. The earth round the spike had been left on the table, and a second sample was loosened and fell in the bedroom. I may add that I walked out to the athletic grounds this morning, saw that tenacious black clay is used in the jumping-pit, and carried away a specimen of it, together with some of the fine tan or sawdust which is strewn over it to prevent the athlete from slipping.