“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 ashore?”

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.”