Harriet shook her head.

“I’m afraid you’re susceptible to fair hair and a slim figure. That in the slender’s but a humorous word which in the stout is flat impertinence.”

“It might have been extremely impertinent, but actually it was not. I shall be interested to know what he makes of tonight’s affair. We’d better go and see if there’s been any more funny business.”

Nothing unusual was, however, to be observed.

Harriet rang up the Mitre before breakfast.

“Peter, could you possibly come round this morning instead of at six o’clock?”

“Within five minutes, when and where you will. ‘If she bid them, they will go barefoot to Jerusalem, to the great Cham’s court, to the East Indies, to fetch her a bird to wear in her hat.’ Has anything happened?”

“Nothing alarming; a little evidence in situ. But you may finish the bacon and eggs.”

“I will be at the Jowett Walk Lodge in half an hour.”

He came accompanied by Bunter and a camera. Harriet took them into the Dean’s room and told them the story, with some assistance from Miss Martin, who asked whether he would like to interview the two scouts.

“Not for the moment. You seem to have asked all the necessary questions. We’ll go and look at the room. There’s no way to it, I take it, except along this passage. Two doors on the left-students’ rooms, I suppose. And one on the right. And the rest bathrooms and things. Which is the door of the darkroom? This? In full view of the other door-so there was no escape except by the window. I see. The key of the lecture-room was inside and the curtain left exactly like that? You’re sure? All right. May I have the key?”

He threw the door open and glanced in.

“Get a photograph of this, Bunter. You have very nice, well-fitting doors in this building. Oak. No paint, no polish.”

He took a lens from his pocket and ran it, rather perfunctorily, over the light-switch and the door-handle.

“Am I really going to see finger-prints discovered?” asked the Dean. “Why, of course,” said Wimsey. “It won’t tell us anything, but it impresses the spectator and inspires confidence. Bunter, the insufflator. You will now see,” he pumped the white powder rapidly over the frame and handle of the door, “how inveterate is the habit of catching hold of doors when you open them.” An astonishing number of superimposed prints sprang into view above the lock as he blew the superfluous powder away. “Hence the excellent old-fashioned institution of the finger-plate. May I borrow a chair from the bathroom?… Oh, thank you, Miss Vane; I didn’t mean you to fetch it.”

He extended the blowing operations right up to the top of the door and the upper edge of the frame.

“You surely don’t expect to find finger-prints up there,” said the Dean. “Nothing would surprise me more. This is merely a shop-window display of thoroughness and efficiency. All a matter of routine, as the policeman says. Your college is kept very well dusted; I congratulate you. Well, that’s that. We will now direct our straining eyes to the dark-room door and do the same thing there. The key? Thank you. Fewer prints here, you see. I deduce that the room is usually approached by way of the lecture-room. That probably also accounts for the presence of dust along the top of the door. Something always gets overlooked, doesn’t it? The linoleum, however, has been honourably swept and polished. Must I go down on my knees and do the floor-walk for footprints? It is shockingly bad for one’s trousers and seldom useful. Let us rather examine the window. Yes-somebody certainly seems to have got out here. But we knew that already. She climbed over the sink and knocked that beaker off the draining-board.”

“She trod in the sink,” said Harriet, “and left a damp smear on the sill. It’s dried up now, of course.”

“Yes; but that proves she really did get out this way and at that time. Though it scarcely needed proving. There is no other way out. This isn’t the old problem of a hermetically-sealed chamber and a body. Have you finished in there, Bunter?”

“Yes, my lord; I have made three exposures.”

“That ought to do. You might clean those doors, would you?” He turned, smiling, on the Dean. “You see, even if we did identify all those fingerprints, they would all belong to people who had a perfect right to be here. And in any case, our culprit, like everybody else these days, probably knows enough to wear gloves.”

He surveyed the lecture-room critically.

“Miss Vane!”

“Yes?”

“Something worried you about this room. What was it?”

“You don’t need to be told.”

“No; I am convinced that our two hearts beat as one. But tell Miss Martin.”

“When the Poison-Pen turned off the light, she must have been close to the door. Then she went out by way of the dark-room. Why did she knock over the blackboard, which is right out of the line between the two doors?”

“Exactly.”

“Oh!” cried the Dean, “but that’s nothing. One often loses one’s way in a dark room. My reading-lamp fused one night, and I got up to try and find the wall-switch and brought up with my nose against the wardrobe.”

“There!” said Wimsey. “The chill voice of common-sense falls on our conjectures like cold water on hot glass, and shatters them to bits. But I don’t believe it. She had only to feel her way along the wall. She must have had some reason for going back into the middle of the room.”

“She’d left something on one of the tables.”

“That’s more likely. But what? Something identifiable.”

“A handkerchief or something that she’d been using to press down the letters as she pasted them on.”

“We’ll say it was that. These papers are just as you found them, I imagine. Did you test them to see if the paste was still wet9”

“I just felt this unfinished one on the floor. You see how it’s done. She drew I a line of paste right across the paper and then dabbed the letters on. The unfinished line was just tacky, but not wet. But then, you see, we didn’t get in till after she’d been gone five or ten minutes.”

“You didn’t test any of the others?”

“I’m afraid not.”

“I only wondered how long she’d been working here. She’s managed to get through a good bit. But we may be able to find out another way.” He took up the box-lid containing the odd letters.

“Rough brown cardboard; I don’t think we’ll bother to look for fingerprints on this. Or to trace it; it might have come from anywhere. She’d nearly finished her job; there are only a couple of dozen letters left, and a lot of them are Q’s and K’s and Z’s and such-like unhandy consonants. I wonder how this last message was meant to end.”

He picked the paper from the floor and turned it over.

“Addressed to you, Miss Vane. Is this the first time you have been honoured?”

“The first time-since the first time.”

“Ah! ‘You needn’t think you’ll get me, you make me laugh, you…’ Well, the epithet remains to be supplied-from the letters in the box. If your vocabulary is large enough you may discover what it was going to be.”

“But… Lord Peter-”

It was so long since she had addressed him by his title that she felt self-conscious about it. But she appreciated his formality.

“What I want to know is, why she came to this room at all.”

“That is the mystery, isn’t it?”

There was a shaded reading-lamp on the table, and he stood idly clicking the light on and off. “Yes. Why couldn’t she do it in her own room? Why invite discovery?”

“Excuse me, my lord.”

“Yes, Bunter?”

“Would this be any contribution to the inquiry?”

Bunter dived beneath the table and came up, holding a long black hairpin.

“Good heavens, Bunter! This is like a leaf out of a forgotten story. How many people use these things?”

“Oh, quite a number, nowadays,” said the Dean. “Little buns in the neck have come back. I use them myself, but mine are bronze ones. And some of the students. And Miss Lydgate-but I think hers are bronze, too.”