"I could swear to him myself," added Langholm. "It remains to be seen whether there is evidence enough to convict."

"Have you communicated with the police?"

"Not yet."

"They seem to have some absurd bee in their helmet down here, you know."

"They don't get it from me."

It was impossible any longer to doubt the import of Langholm's earnest and rather agitated manner. He was doing his best to suppress his agitation, but that strengthened the impression that he had indeed discovered something which he himself honestly believed to be the truth. There was an immediate alteration in the tone and bearing of his host.

"My dear fellow," he said, "forgive my levity. If you have really found out anything, it is a miracle; but miracles do happen now and then. Here's the pond, and there's the boathouse behind those rhododendrons. Suppose you tell me the rest in the boat? We needn't keep looking over our shoulders in the middle of the pond!"

For an instant Langholm dreamt of the readiest and the vilest resource; in another he remembered, not only that he could swim, but the insidious sympathy for this man which a darker scoundrel had sown in his heart. It had grown there like Jonah's gourd; only his flippancy affected it; and Steel was far from flippant now. Langholm signed to him to lead the way, and in a very few minutes they were scaring the wildfowl in mid-water, Steel sculling from the after thwart, while Langholm faced him from the crimson cushions.

"I thought," said the latter, "that I would like to tell you what sort of evidence I could get against him before-before going any further. I-I thought it would be fair."

Steel raised his bushy eyebrows the fraction of an inch. "It would be fairest to yourself, I agree. Two heads are better than one, and-well, I'm open to conviction still, of course."

But even Langholm was not conscious of the sinister play upon words; he had taken out his pocket-book, and was nervously turning to the leaves that he had filled during his most sleepless night in town.

"Got it all down?" said Steel.

"Yes," replied Langholm, without raising his eyes; "at least I did make some notes of a possible-if not a really d.a.m.ning-case against the man I mean."

"And what may the first point be?" inquired Steel, who was gradually drifting back into the tone which Langholm had resented on the sh.o.r.e; he took no notice of it now.

"The first point," said Langholm, slowly, "is that he was in Chelsea, or at least within a mile of the scene of the murder, on the night that it took place."

"So were a good many people," remarked Steel, smiling as he dipped the sculls in and out, and let his supple wrists fall for the feather, as though he were really rowing.

"But he left his-he was out at the time!" declared Langholm, making his amended statement with all the meaning it had for himself.

"Well, you can't hang him for that."

"He will have to prove where he was, then."

"I am afraid it will be for you to prove a little more first."

Langholm sat very dogged with his notes. There had been a pause on Steel's part; there was a thin new note in his voice. Langholm was too grimly engrossed to take immediate heed of either detail, or to watch the swift changes in the face which was watching him. And there he lost most of all.

"The next point is that he undoubtedly knew Minchin in Australia-"

"Aha!"

"That he was and is a rich man, whereas Minchin was then on the verge of bankruptcy, and that Minchin only found out that he was in England thirty-six hours before his own death, when he wrote to his old friend for funds."

"And you have really established all that!"

Steel had abandoned all pretence of rowing; his tone was one of admiration, in both senses of the word, and his dark eyes seemed to penetrate to the back of Langholm's brain.

"I can establish it," was the reply.

"Well! I think you have done wonders; but you will have to do something more before they will listen to you at Scotland Yard. What about a motive?"

"I was coming to that; it is the last point with which I shall trouble you for the present." Langholm took a final glance at his notes, then shut the pocket-book and put it away. "The motive," he continued, meeting Steel's eyes at last, with a new boldness in his own-"the motive is self-defence! There can be no doubt about it; there cannot be the slightest doubt that Minchin intended blackmailing this man, at least to the extent of his own indebtedness in the City of London."

"Blackmailing him?"

There was a further change of voice and manner; and this time nothing was lost upon Charles Langholm.

"There cannot be the slightest doubt," he reiterated, "that Minchin was in possession of a secret concerning the man in my mind, which secret he was determined to use for his own ends."

Steel sat motionless, his eyes upon the bottom of the boat. It was absolutely impossible to read the lowered face; even when at length he raised it, and looked Langholm in the eyes once more, the natural inscrutability of the man was only more complete than ever.

"So that is your case!" said he.

And even his tone might have been inspired either by awe or by contempt, so truly rang the note between the two.

"I should be sorry to have to meet it," observed Langholm, "if I were he."

"I should find out a little more," was the retort, "if I were you!"

"And then?"

"Oh, then I should do my duty like a man-and take all the emoluments I could."

The sneer was intolerable. Langholm turned the color of brick.

"I shall!" said he through his mustache. "I have consulted you; there will be no need to do so again. I shall make a point of taking you at your word. And now do you mind putting me ash.o.r.e?"

A few raindrops were falling when they reached the landing-stage; they hurried to the house, to find that Langholm's bicycle had been removed from the place where he had left it by the front entrance.

"Don't let anybody trouble," he said, ungraciously enough, for he was still smarting from the other's sneer. "I can soon find it for myself."

Steel stood on the steps, his midnight eyes upon Langholm, the glint of a smile in those eyes, but not the vestige of one upon his lips.

"Oh, very well," said he. "You know the side-door near the billiard-room? They have probably put it in the first room on the left; that is where we keep ours-for we have gone in for them at last. Good-by, Langholm; remember my advice."

And, that no ceremony should be lost between them, the host turned on his heel and disappeared through his own front door, leaving Langholm very angry in the rain.

But anger was the last emotion for such an hour; the judge might as well feel exasperated with the prisoner at the bar, the common hangman with the felon on the drop. Langholm only wished that, on even one moment's reflection, he could rest content in so primitive and so single a state of mind. He knew well that he could not, and that every subtle sort of contest lay before him, his own soul the arena. In the meantime let him find his bicycle and get away from this dear and accursed spot; for dear it had been to him, all that too memorable summer; but now of a surety the curse of Cain brooded over its cold, white walls and deep-set windows like sunken eyes in a dead face.

Langholm found the room to which he had been directed; in fact, he knew it of old. And there were the two new Beeston Humbers; but their l.u.s.trous plating and immaculate enamel did not shame his own old disreputable roadster, for the missing machine certainly was not there. Langholm was turning away when the glazed gun-rack caught his eye. Yes, this was the room in which the guns were kept. He had often seen them there. They had never interested him before. Langholm was no shot. Yet now he peered through the gla.s.s-gasped-and opened one of the sliding panels with trembling hand.

There on a nail hung an old revolver, out of place, rusty, most conspicuous; and at a glance as like the relic in the Black Museum as one pea to another. But Langholm took it down to make sure. And the maker's name upon the barrel was the name that he had noted down at the Black Museum; the point gained, the last of the cardinal points postulated by the official who had shown him round.

The fortuitous discoverer of them all was leaving like a thief-more and more did Langholm feel himself the criminal-when the inner door opened and Steel himself stood beaming sardonically upon him.