"Good-morning, Inspector," said Robin affably, "you're early to work, I see. Having a little experiment, eh?"

Manderton nodded without replying. Then the stentorian tones of Sergeant Harris proclaiming the views of "The Thunderer" on the Silesian situation rolled down the corridor and struck distinctly on the ears of the listeners in the hall.

Presently Manderton closed the corridor door, shutting off the sound abruptly.

"I think you said you could not hear the sergeant with the library door shut?" queried Robin suavely.

"With the door shut--no," answered the detective shortly. "But with the door open ..."

He broke off significantly and dropped his eyes to his boots.

"Would it be troubling you," Robin struck in, "if we pushed your experiment one step farther?"

Manderton lifted his eyes and looked at the young man, Robin met his gaze unflinchingly.

"Well?"

There was no invitation in his voice, but Robin affected to disregard the other's coldness.

"Let the library door be shut," said Robin, "but leave the gla.s.s door leading into the garden open. Then give Sergeant Harris another trial at his reading...."

The detective smiled rather condescendingly.

"With the library door shut, you'll hear nothing," he remarked.

"The library window is open," Robin retorted, "or rather it is as good as open, as one of the two big panes is smashed...."

His voice vibrated with eagerness. The detective looked at him curiously.

"Oh, try if you like," he said carelessly.

Without waiting for his a.s.sent, Robin had already plucked open the corridor door and was halfway down the pa.s.sage as the other replied. He was back again almost at once and, motioning the detective to silence, took his place at his side by the open door. Then the sound of the policeman's voice was heard from the corridor. It was m.u.f.fled and indistinct so that the sense of his words could not be made out. But the voice was audible enough.

Robin turned to the detective.

"Bude could make out no words," he said.

"But how do we know that the gla.s.s door was open?" queried the detective sceptically.

"Because I left it open myself," Robin countered promptly, "when I went out for my walk before tea. Sir Horace told me that he found the door banging about in the wind when he went out to get into the library by the window."

Mr. Manderton allowed his fat, serious face to expand very slowly into a broad, superior smile.

"Doesn't it seem a little curious," he said, "that Mr. Hartley Parrish should choose to sit and work in the library on a gusty and dark winter evening with the window wide open? You'll allow, I think, that the window was not broken until after his death ..."

Robin's nerves were ragged. The man's tone nettled him exceedingly. But he confined himself to making a little gesture of impatience.

"No, no, sir," said Mr. Manderton, very decidedly, "I prefer to think that the library door was open, left open by the party who went in to speak to Mr. Parrish yesterday afternoon ... and who knows more about the gentleman's suicide than he would have people think ..."

Robin boiled over fairly at this.

"Good G.o.d, man!" he exclaimed, "do you accept this theory of suicide as blandly as all that? Have you examined the body? Don't you use your eyes? I tell you ... bah, what's the use? I'm not here to do your work for you!..."

"No, sir," said the detective, quite unruffled, "you are not. And I think I'll continue to see about it myself!"

With that he opened the corridor door and vanished down the pa.s.sage.

With great deliberation Robin selected a cigarette from his case, lit it, and walked out through the front door into the fresh air again. More than ever he felt the riddle of Hartley Parrish's death weighing upon his mind.

His intuitive sense rebelled against the theory of suicide, despite the medical evidence, despite the revolver in the dead man's hand, despite the detective's a.s.surance. And floating about in his brain, like the gossamer on the glistening bushes in the gardens, were broken threads of vague suspicions, of half-formed theories, leading from his hasty observations in the death chamber ...

In itself the death of Hartley Parrish left him cold. Yes, he must admit that. But the look in Mary Trevert's eyes, as she had urged him to shield himself from the suspicion of having driven Hartley Parrish to his death, haunted him. Already dimly he was beginning to realize that Hartley Parrish in death might prove as insuperable a bar between him and Mary Trevert as ever he had been in life ...

She was now a wealthy woman. Hartley Parrish's will had ensured that, he knew. But it was not the barrier of riches that Robin Greve feared. He had asked Mary Trevert to be his wife before there was any thought of her inheriting Parrish's fortune. He derived a little consolation from that reflection. At least he could not appear as a fortune-hunter in her eyes. But, until he could clear himself of the suspicion lurking in Mary Trevert's mind that he, Robin Greve, was in some way implicated in Hartley Parrish's death, the dead man, he felt, would always stand between them. And so ...

Robin pitched the stump of his cigarette into a rose bush with a little gesture of resignation. Almost without knowing it, he had strolled into the rosery up a shallow flight of steps cut into the bank of green turf, which ran along the side of the house facing the library window to the corner of the house where it met the clipped box-hedge of the Pleasure Ground.

The rosery was a pleasant rectangle framed in a sort of rustic bower which in the summer was covered with superb roses of every hue and variety. Gravel paths intersected rose-beds cut into all manner of fantastic shapes where stood the slender shoots of the young rose-trees each with its tag setting forth its kind, for Hartley Parrish had been an enthusiastic amateur in this direction.

Robin turned round and faced the house. From his elevation he could look down into the library through the window with its shattered pane. He could see the gleaming polish on Hartley Parrish's big desk and the great arm-chair pushed back as Hartley Parrish had pushed it from him just before his death.

The bare poles of the woodwork festooned with the black arms of the creeping roses, standing out dark in the fast falling winter evening, must, he reflected, have been the last view that Hartley Parrish had had before ...

But then he broke off his meditations abruptly. His eye had fallen on a narrow white patch standing out on one of the uprights supporting the clambering roses.

It was a stout young tree, the light brown bark left adhering to its surface. It was a long blaze on the bark on the side of the trunk which had caught his eye. Robin walked round the gravel path until he was within a foot of the pole to get a better view.

The pole stood almost exactly opposite the library window. The scar in the bark was high up and diagonal and quite freshly made, for the wood was dead white and much splintered.

The young man put a hand on the upright for support and leant forward, carefully refraining from putting his foot on the soft brown mould of the flower-bed which fringed the path between it and the rustic woodwork. Then he ran lightly down the steps until he stood with his back to the library window. From here he carefully surveyed the upright again, then, returning to the rosery, began a careful scrutiny of the gravel paths and the beds.

Apparently his search gave little result, for he presently abandoned it and turned his attention to the wooden framework on the other side of the rectangular rose-garden. He plunged boldly in among the rose-bushes and examined each upright in turn. He spent about half an hour in this meticulous investigation, and then, his boots covered with mould, his rough shooting-coat glistening with moisture, he walked slowly down the steps and reentered the house.

As he was wiping the mud off his boots on the great mat in the front hall, Bude came out of the lounge hall with a pile of dishes on a tray.

"Bude," said Robin, "can you tell me if the fire in the library has been smoking of late?"

"Well, sir," replied the butler, "we've always had trouble with that chimdy when the wind's in the southwest."

"Has it been smoking lately?" The young man reiterated his question impatiently.

The man looked up in surprise.

"Well, sir, now you come to mention it, it has. As a matter o'fact, sir, the sweep was ordered for to-day ..."

"Why?"

"Well, sir, Mr. Parrish had mentioned it to me ..."