Shelving the problem of the visitor’s exit for the time being, Roger began to puzzle over that laconically worded document.
During the next quarter of an hour Roger himself might have presented a problem to an acute observer, had there been one about, which, though not very difficult of solution, was nevertheless not entirely without interest. To smoke furiously, with one’s pipe in full blast, betokens no small a degree of mental excitement; to sit like a stone image and allow that same pipe to go out in one’s mouth is evidence of still greater prepossession; but what are we to say of a man who, after passing through these successive stages, smokes away equally furiously at a perfectly cold pipe under the obvious impression that it is in as full blast as before? And that is what Roger was doing for fully three minutes before he finally jumped suddenly to his feet and hurried off once again to that happy hunting ground of his, the library.
There Alec found him twenty minutes later, when the car had departed irrevocably for the station. A decidedly more cheerful Alec than that of the morning, one might note in passing; and not looking in the least like a young man who has just parted with his lady for a whole month. It is a reasonable assumption that Alec had not been wasting the last half hour.
“Still at it?” he grinned from the doorway. “I had a sort of idea I should find you here.”
Roger was a-quiver with excitement. He scrambled up from his knees beside the wastepaper basket, into which he had been peering, and flourished a piece of paper in the other’s face.
“I’m on the track!” he exclaimed. “I’m on the track, Alexander, in spite of your miserable sneers. Nobody around, is there?”
Alec shook his head. “Well? What have you discovered now?” he asked tolerantly.
Roger gripped his arm and drew him towards the writing table. With an eager finger he stubbed at the blotter.
“See that?” he demanded.
Alec bent and scrutinised the blotter attentively. Just in front of Roger’s finger were a number of short lines not more than an inch or so long. The ones at the left-hand end were little more than scratches on the surface, not inked at all; those in the middle bore faint traces of ink; while towards the right end the ink was bold and the lines thick and decided. Beyond these were a few circular blots of ink. Apart from these markings, the sheet of white blotting paper, clearly fresh within the last day or two, had scarcely been used.
“Well?” said Roger triumphantly. “Make anything of it?”
“Nothing in particular,” Alec confessed, straightening up again. “I should say that somebody had been cleaning his pen on it.”
“In that case,” Roger returned with complacency, “it would become my painful duty to inform you that you were completely wrong.”
“Why? I don’t see it.”
“Then look again. If he had been cleaning his pen, Alexander Watson, the change from ink to the lack of it would surely be from left to right, wouldn’t it? Not from right to left?”
“Would it? He might have moved from right to left.”
“It isn’t natural. Besides, look at these little strokes. Nearly all of them have a slight curve in the tail towards the right. That means they must have been made from left to right. Guess again.”
“Oh, well, let’s try the reverse,” said Alec, nettled into irony. “He wasn’t cleaning his pen at all; he was dirtying it.”
“Meaning that he had dipped it in the ink and was just trying it out? Nearer. But take another look, especially at this left-hand end. Don’t you see where the nib has split in the centre to make these two parallel furrows? Well, just observe not only how far apart those furrows are, but also the fact that, though pretty deep, there isn’t a sign of a scratch. Now, then, what does all that tell you? There’s only one sort of pen that could have made those marks, and the answer to that tells you what the marks are.”
Alec pondered dutifully. “A fountain pen! And he was trying to make it write.”
“Wonderful! Alec, I can see you’re going to be a tremendous help in this little game.”
“Well, I don’t see anything to make such a fuss about, even if they were made by a fountain pen. I mean, it doesn’t seem to take us any forrader.”
“Oh, doesn’t it?” Roger had an excellent though somewhat irritating sense of the dramatic. He paused impressively.
“Well?” asked Alec impatiently. “You’ve got something up your sleeve, I know, and you’re aching to get it out. Let’s have it. What do these wonderful marks of yours show you?”
“Simply that the confession is a fake,” retorted Roger happily. “And now let’s go out in the garden.”
He turned on his heel and walked rapidly out on to the sun-drenched lawn. One must admit that Roger had his annoying moments.
The justly exasperated Alec trotted after him. “Talk about Sherlock Holmes!” he growled, as he caught him up. “You’re every bit as maddening yourself. Why can’t you tell me all about it straight out if you really have discovered something, instead of beating about the bush like this?”
“But I have told you, Alexander,” said Roger, with an air of bland innocence. “That confession is a fake.”
“But why?”
Roger hooked his arm through that of the other and piloted him in the direction of the rose garden.
“I want to stick around here,” he explained, “so as to see the inspector when he comes up the drive. I’m not going
