“All right,” answered Van Koon.  He turned to Allerdyke and Mrs. Marlow.  “Ever since this affair was brought under my notice,” he said, “I’ve pointed out to Fullaway certain features in connection with it.  First—­there’s no evidence whatever that this plot originated in or was worked from Russia.  Second—­there is evidence that it began here in London and was carried out from London.  And following on that second proposition comes another.  Fullaway knew that these jewels were coming—­”

He paused and gave the secretary a keen look.  And Allerdyke, watching her just as keenly, saw her face and eyes as calm and inscrutable as ever; it was absolutely evident that nothing could move this woman, no chance word or allusion take her unawares.  Van Koon smiled, and leaned nearer.

“But,” he said, tapping the table in emphasis of his words, “there was somebody else who knew of this deal, somebody whose name Fullaway there steadfastly refuses to bring in.  Delkin!”

Fullaway suddenly laughed, throwing up his arms.

“Delkin!” he exclaimed satirically.  “A millionaire several times over!  The thing’s ridiculous, Van Koon!  Delkin would kick me out if I went and asked him—­”

“Delkin will have to be asked,” interrupted Van Koon.  “You will not face the facts, Fullaway.  Millionaire, multimillionaire, Delkin was the third person (I’m leaving this valet, Ebers, clean out, though I’ve not the slightest doubt he was one of the pieces of the machine) who knew that James Allerdyke was bringing two hundred and fifty thousand pounds’ worth of jewels for his, Delkin’s approval!  That’s a fact, Fullaway, which cannot be got over.”

“Psha!” exclaimed Fullaway.  “I suppose you think Delkin, who could buy up the best jeweller’s shop in London or Paris and throw its contents to the street children to play with—­”

“What is it that’s in your mind, Mr. Van Koon?” asked Allerdyke, interrupting Fullaway’s eloquence.  “You’ve some theory?”

“Well, I don’t know about theory,” answered Van Koon, “but I guess I’ve got some natural common sense.  If Fullaway there thinks I’m suggesting that Delkin organized a grand conspiracy to rob James Allerdyke, Fullaway’s wrong—­I’m not.  What I am suggesting, and have been suggesting this last three days, is that Delkin should be asked a plain and simple question, which is this—­did he ever tell anybody of this proposed deal?  If so—­whom did he tell?  And if that isn’t business,” concluded Van Koon, “then I don’t know business when I see it!”

“What’s your objection?” asked Allerdyke, looking across at Fullaway.  “What objection can you have?”

Fullaway shook his head.

“Oh, I don’t know!” he said.  “Except that it seems immaterial, and that I don’t want to bother Delkin.  I’m hoping that these jewels will be found, and that I’ll be able to complete the transaction, and—­besides, I don’t believe for one instant that Delkin would tell anybody.  I only had two interviews with Delkin—­one at his hotel, one here.  He understood the affair was an entirely private and secret transaction.”