He stopped me with a sharp move of the hand.

"Don't go over all that!" he said. "It's a waste of time. The point is, that necklace is not your friend's. But I'm going to tell you what it is. It's a duplicate of it, stone for stone. The lady, I think, will agree with me on that. Am I right?"

The girl nodded.

"Then what the devil's this man doing with it?" demanded Benny Churchill, before any of us could speak.

"S'pose you wait and find out who this man is!"

"Well, who is he?" I inquired, resolved that no hand, however artful, was going to pull the wool over my eyes.

"This man," said my unperturbed and big-shouldered friend, "is the pearl-matcher for Cohen and Greenhut, the Maiden Lane importers. Wait, don't interrupt me. Miss Churchill's necklace, I understand, was one of the finest in this town. His house had an order to duplicate it.

He took the first chance, when the pearls had been matched and strung, to see that he'd done his job right."

"And you mean to tell me," I cried, "that he hung over a box-rail and lifted a string of pearls from a lady's neck just to--"

"Hold on there, my friend," cut in the big-limbed man. "He found this lady was going to be in that box wearin' that necklace."

"And having reviewed its chaste beauty, he sneaked out of his own box and ran like a chased cur!"

"Hold your horses now! Can't you see that he thought you were the crook? If you had a bunch of stones like that on you and a stranger b.u.t.ted in and started trailin' you, wouldn't you do your best to melt away when you had the chance?" demanded the officer. Then he looked at me again with his wearily uplifted eyebrows. "Oh, I guess you were all right as far as you went, but, like most amateurs, you didn't go quite far enough!"

It was Benny Churchill who spoke up before I could answer. His voice, as he spoke, was oddly thin and childlike.

"But why in heaven's name should he want to duplicate my sister's jewelry?"

"For another woman, with more money than brains, or the know-how, or whatever you want to call it," was the impa.s.sive response.

I saw the girl across the table from me push the necklace away from her, and leave it lying there in a glimmering heap on the white table.

I promptly and quietly reached out and took possession of it, for I still had my own ideas of the situation.

"That's all very well," I cried, "and very interesting. But what I want to know is: _who got the first necklace?_"

The big-framed man looked once more at his watch. Then he looked a little wearily at me.

"I got 'em!"

"You've got them?" echoed both the girl and her brother. It was plain that the inconsequentialities of the last hour had been a little too much for them.

The man thrust a huge hand down in the pocket of his damp and somewhat unshapely overcoat.

"Yes, I got 'em here," he explained as he drew his hand away and held the glimmering string up to the light. "I picked 'em up from the corner of that box where they slipped off the lady's neck."

He rose placidly and ponderously to his feet.

"And I guess that's about all," he added as he squinted through an uncurtained strip of plate gla.s.s and slowly turned up his coat collar, "except that some of us outdoor guys'll sure get webfooted if this rain keeps up!"

CHAPTER X

THE THUMB-TAP CLUE

I was being followed. Of that there was no longer a shadow of doubt.

Move by move and turn by turn, for even longer than I had been openly aware of it, some one had been quietly shadowing me.

Now, if one thing more than another stirs the blood of the man who has occasion to walk by night, it is the discovery that his steps are being dogged. The thought of being watched, of having a possible enemy behind one, wakens a thrill that is ancestral.

So, instead of continuing my busily aimless circuit about that high-spiked iron fence which encloses Gramercy Park, I shot off at a tangent, continuing from its northwest corner in a straight line toward Fourth Avenue and Broadway.

I had thought myself alone in that midnight abode of quietness. Only the dread of a second sleepless night had kept me there, goading me on in my febrile revolutions until weariness should send me stumbling off my circuit like a six-day rider off his wheel.

Once I was in the house-shadows where Twenty-first Street again begins I swung about and waited. I stood there, in a sort of quiet belligerency, watching the figure of the man who had been d.o.g.g.i.ng my steps. I saw him turn southward in the square, as though my flight were a matter of indifference to him. Yet the sudden relieving thought that his movements might have been as aimless as my own was swallowed up by a second and more interesting discovery.

It was the discovery that the man whom I had accepted as following me was in turn being followed by yet another man.

I waited until this strange pair had made a full circuit of the iron-fenced enclosure. Then I turned back into the square, walking southward until I came opposite my own house door. The second man must have seen me as I did so. Apparently suspicious of possible espionage, he loitered with a.s.sumed carelessness at the park's southern corner.

The first man, the slighter and younger-looking figure of the two, kept on his unheeding way, as though he were the ghost-like compet.i.tor in some endless nightmare of a Marathon.

My contemplation of him was interrupted by the advent of a fourth figure, a figure which seemed to bring something sane and rea.s.suring to a situation that was momentarily growing more ridiculous. For the newcomer was McCooey, the patrolman. He swung around to me without speaking, like a ferry swinging into its slip. Then he stood looking impa.s.sively up at the impa.s.sive November stars.

"Yuh're out late," he finally commented, with that careless ponderosity which is the step-child of unquestioned authority.

"McCooey," I said, "there's a night prowler going around this park of yours. He's doing it for about the one hundred and tenth time. And I wish you'd find out what in heaven he means by it."

"Been disturbin' yuh?" casually asked the law incarnate. Yet he put the question as an indulgent physician might to a patient. McCooey was of that type which it is both a joy and a temptation to mystify.

"He's a.s.saulted my curiosity," I solemnly complained.

"D' yuh mean he's been interferin' wid yuh?" demanded my literal friend.

"I mean he's invaded my peace of mind."

"Then I'll see what he's afther," was the other's answer. And a moment later he was swinging negligently out across the pavement at a line which would converge with the path of the nervously pacing stranger. I could see the two round the corner almost together. I could see McCooey draw nearer and nearer. I could even see that he had turned and spoken to the night walker as they went down the square together past the lights of the Players.

I could see that this night-walker showed neither resentment nor alarm at being so accosted. And I could also see that the meeting of the two was a source of much mystification to the third man, the man who still kept a discreet watch from the street corner on my right.

McCooey swung back to where I stood. He swung back resentfully, like a retriever who had been sent on a blind trail.

"What's he after, anyway?" I irritably inquired.

"He says he's afther sleep!"

"After what?" I demanded.

McCooey blinked up at a sky suddenly reddened by an East River gas-flare. Then he took a deep and disinterested breath.

"He says he's afther sleep," repeated the patrolman. "Unless he gets her, says he, he's goin to walk into the East River."