I let out a fine exclamation when I saw that, and the other three turned and stared at me.

“Mr. Lindsey!” said I, “look here!  Those are the clothes he was wearing when I saw the last of him.  And there’s the shirt he had on, too, and the shoes.  Wherever he is, and whatever happened to him, he made a complete change of linen and clothing before he quitted the yacht!  That’s a plain fact, Mr. Lindsey!”

A fact it was—­and one that made me think, however it affected the others.  It disposed, for instance, of any notion or theory of suicide.  A man doesn’t change his clothes if he’s going to drown himself.  And it looked as if this had been part of some premeditated plan:  at the very least of it, it was a curious thing.

“You’re sure of that?” inquired Mr. Lindsey, eyeing the things that had been thrown aside.

“Dead sure of it!” said I.  “I couldn’t be mistaken.”

“Did he bring a portmanteau or anything aboard with him, then?” asked he.

“He didn’t; but he could have kept clothes and linen and the like in these lockers,” I pointed out, beginning to lift the lids.  “See here!—­here’s brushes and combs and the like.  I tell you before ever he left this yacht, or fell out of it, or whatever’s happened him, he’d changed everything from his toe to his top—­there’s the very cap he was wearing.”

They all looked at each other, and Mr. Lindsey’s gaze finally fastened itself on Andrew Robertson.

“I suppose you don’t know anything about this, my friend?” he asked.

“What should I know?” answered Robertson, a bit surlily.  “The yacht’s just as I found it—­not a thing’s been touched.”

There was the luncheon basket lying on the cabin table—­just as I had last seen it, except that Carstairs had evidently finished the provisions which he and I had left.  And I think the same thought occurred to Mr. Lindsey and myself at the same moment—­how long had he stopped on board that yacht after his cruel abandoning of me?  For forty-eight hours had elapsed since that episode, and in forty-eight hours a man may do a great deal in the way of making himself scarce—­which now seemed to me to be precisely what Sir Gilbert Carstairs had done, though in what particular fashion, and exactly why, it was beyond either of us to surmise.

“I suppose no one has heard anything of this yacht having been seen drifting about yesterday, or during last night?” asked Mr. Lindsey, putting his question to both men.  “No talk of it hereabouts?”

But neither the police nor Andrew Robertson had heard a murmur of that nature, and there was evidently nothing to be got out of them more than we had already got.  Nor had the police heard of any stranger being seen about there—­though, as the man who was with us observed, there was no great likelihood of anybody noticing a stranger, for Largo was nowadays a somewhat popular seaside resort, and down there on the beach there were many strangers, it being summer, and holiday time, so that a strange man more or less would pass unobserved.