Bisset laid on the table a sheet of note paper.

"Here," said he, "is a kin' of bit sketch plan of the library. Observing this plan attentively, you will notice two crosses, marked A and B. A is where yon wee table was standing—no the place against the wall where it was standing this morning, but where it was standing before it was knocked over last night. B is where the corp was found. You follow that, sir?"

Ned nodded.

"I follow," said he.

"Now, the principle in a' these cases of crime and detection," resumed the philosopher, assuming his lecturer's air, "is noticing such sma' points of detail as escape the eye of the ordinar' observer, taking full and accurate measurements, making a plan with the principal sites carefully markit, and drawing, as it were, logical conclusions. Applying this method now to the present instance, Mr. Cromarty, the first point to observe is that the room is twenty-six feet long, measured from the windie, which is a bit recessed or set back, as it were, to the other end of the apartment. Half of 26 is 13, and if you take the half way line and draw approximate perpendiculars to about where the table was standing and to as near as one can remember where the middle of the corp roughly was lying, you get exactly six feet ten and five-eighths inches, in both cases."

"An approximate perpendicular to roughly about these places gives this exact measurement?" repeated Cromarty gravely. "Well, what next?"

"Well, sir, I'll not insist too much on the coincidence, but it seems to me vera remarkable. But the two significant features of this case seem to me yon table being upset over by the windie and the corp being found over by the door."

"You're talking horse sense now," murmured Ned.

"Now, yon table was upset by Sir Reginald falling on it!"

Ned looked at him keenly.

"How do you know?"

"Because one of the legs was broken clean off!"

"What, when we saw it this morning?"

"We had none of us noticed it then, sir; but I've had a look at it since, and there's one leg broken fair off at the top. The break was half in the socket, as it were, leaving a kind of spike, and if you stick that into the socket you can make the table look as good as new. It's all right, in fac', until you try to move it, and then of course the leg just drops out."

"And it wasn't like that yesterday?"

"I happened to move it myself not so long before Sir Reginald came into the room, and that's how I know for certain where it was standing and that it wasn't broken. And yon wee light tables dinna lose their legs just with being cowped, supposing there was nothing else than that to smash them. No, sir, it was poor Sir Reginald falling on top of it that smashed yon leg."

"Then he was certainly struck down near the window!"

"Well, we'll see that in a minute. It's no in reason, Mr. Cromarty, to suppose he deliberately opened the windie to let his ain murderer in. And it's a' just stuff and nonsense to suggest Sir Reginald was sitting on a winter's night—or next door to winter onyhow, with his windie wide open. I'm too well acquaint with his habits to believe that for a minute. And it's impossible the man can have opened a snibbed windie and got in, with some one sitting in the room, and no alarm given. So it's perfectly certain the man must have come in at the door. That's a fair deduction, is it not, sir?"

Ned Cromarty frowned into space in silence. When he spoke it seemed to be as much to himself as to Bisset.

"How did the window get unsnibbed? Everything beats me, but that beats me fairly."

"Well, sir, Mr. Rattar may no be just exac'ly as intellectual as me and you, but I think there's maybe something in his idea it was done to put us off the scent."

"Possibly—but it strikes me as a derned feeble dodge. However, what's your next conclusion?"

"My next conclusion is, sir, that Simon Rattar may not be so vera far wrong either about Sir Reginald hearing some one at the door and starting to see who it was. Then—bang!—the door would suddenly open, and afore he'd time to speak, the man had given him a bat on the heid that finished him."

"And where does the table come in?"

"Well, my explanation is just this, that Sir Reginald suspected something and took the wee table as a kind of weapon."

"Rot!" said Ned ruthlessly. "You think he left the fireplace and went round by the window to fetch such a useless weapon as that?"

James Bisset was not easily damped.

"That's only a possibility, sir. Excluding that, what must have happened? For that's the way, Mr. Cromarty, to get at the fac's; you just exclude what's not possible and what remains is the truth. If you'd read——"

"Well, come on. What's your theory now?"

"Just that Sir Reginald backed away from the door with the man after him, till he got to the table. And then down went him and the table together."

"And why didn't he cry out or raise the alarm in some way while he was backing away?"

"God, but that fits into my other deductions fine!" cried Bisset. "I hadna thought of that. Just wait, sir, till you see how the case is going to hang together in a minute."

"But how did Sir Reginald's body come to be lying near the door?"

The philosopher seemed to be inspired afresh.

"The man clearly meant to take it away and hide it somewhere—that'll be just it! And then he found it ower heavy and decided to leave it after all."

"And who was this man?"

"That's precisely where proper principles, Mr. Cromarty, lead to a number of vera interesting and instructive discoveries, and I think ye'll see, sir, that the noose is on the road to his neck already. I've not got the actual man, mind! In fac' I've no idea who he is, but I can tell you a good few things about him—enough, in fac', to make escape practically impossible. In the first place, he was one well acquaint with the ways of the house. Is that not a fair deduction, sir?"

"Sure!" said Ned. "I've put my bottom dollar on that already."

"He came from inside this house and not outside it. How long he'd been in the house, that I cannot say, but my own deductions are he'd been in the house waiting for his chance for a good while before the master heard him at yon door. Is that not a fair deduction too, sir?"

"It's possible," said Ned, though not with great conviction.

"And now here's a point that accounts for Sir Reginald giving no alarm—Sir Reginald knew the man and couldna believe he meant mischief!"

Ned looked at him quickly and curiously.

"Well?" said he.

"Is that not a fair deduction, Mr. Cromarty?"

"Seems to fill the bill."

"And now, here's a few personal details. Yon man was a fair active strong man to have dealt with the master the way he did. But he was not strong enough to carry off the corp like a sack of potatoes; he was no a great muckle big giant, that's to say. And finally, calculating from the distance the body was from the door and the number of steps he would be likely to take to the door, and sae arriving at his stride and deducing his height accordingly, he'd be as near as may be five feet nine inches tall. Now, sir, me and you ought to get him with a' that known!"

Ned Cromarty looked at him with a curious gleam in his eye.

"What's your own height, Bisset?" he enquired.

"Five feet nine inches," said the reasoner promptly, and then suddenly his mouth fell open but his voice ceased.

"And now," pursued Ned with a grimly humorous look, "can you not think of a man just that height, pretty hefty but not a giant, who was certainly in the house last night, who knew all the ways of it, and who would never have been suspected by Sir Reginald of meaning mischief?"

"God!" exclaimed the unfortunate reasoner. "I've proved it was mysel'!"

"Well, and what shall I do—string you up now or hand you over to the police?"

"But, Mr. Cromarty—you don't believe that's right surely?"

Tragic though the occasion was, Ned could not refrain from one brief laugh. And then his face set hard again and he said:

"No, Bisset, I do not believe it was you. In fact, I wouldn't believe it was you if you confessed to it. But I'd advise you not to go spreading your deductions abroad! Deduction's a game that wants a bit more practice than you or I have had."

It is possible that James Bisset had never looked quite so crestfallen in his life.

"Then that's all nonsense I've been talking, sir?" he said lugubriously.

"No," said Ned emphatically. "I'll not say that either. You've brought out some good points—that broken table, the place the body was found, the possible reason why Sir Reginald gave no alarm; seems to me those have something to them. But what they mean—what to conclude; we're as far off that, Bisset, as ever!"

The philosopher's self esteem was evidently returning as fast as it had gone.

"Then you wouldn't think there would be any harm, sir, in my continuing my investigations?"

"On your present lines, the only harm is likely to be to yourself. Keep at it—but don't hang yourself accidentally. And let me know if you discover anything else—mind that."

"I'll mind on it, no fears, Mr. Cromarty!"

Ned left him with an expression on his countenance which indicated that the deductive process had already been resumed.

Till he arrived at his own door, the laird of Stanesland was unconscious of a single incident of his drive home. All the way his eye stared straight into space. Sometimes a gleam would light it for an instant, and then he would shake his head and the gleam would fade away.

"I can see neither a damned head nor a damned tail to it!" he said to himself as he alighted.