“Good—­good!” he said.  “Good, Ambler!  That was a bit of right work, and hang me if I don’t believe we shall find something out.  But what’s to be done?  You know, if these two are in at it, they may slip.  That ’ud never do!”

“I don’t think there’s any fear of that—­yet,” answered Appleyard.  “The probability is that neither has any suspicion of being watched—­the whole thing’s so clever that they probably believe themselves safe.  Of course, mind you, this man Rayner may be as innocent as you or I. But against her, on the facts of that photograph affair, there’s a prima facie case.  Only—­don’t let’s spoil things by undue haste or rashness.  I’ve thought things out a good deal, and we can do a lot, you and me, before going to the police, though I don’t think it ’ud do any harm to tell this man Chettle, supposing he were here—­because his discovery of that photo is the real thing.”

“What can we do, then?” asked Allerdyke.

“Make use of the two Gaffneys,” answered Appleyard without hesitation.  “They’re smart chaps—–­real keen ’uns.  We want to find out who Rayner is; what his connection, if any, with Miss Slade, alias Mrs. Marlow, is; who she is, and why she goes under two names.  That’s all what you might call initial proceedings.  What I propose is this—­when you go back to your hotel, get Gaffney into your private sitting-room.  You, of course, know him much better than I do, but from what bit I’ve seen of him I’m sure he’s the sort of man one can trust.  Tell him to get hold of that brother of his and bring him here at any hour you like to-morrow, and then—­well, we can have a conference, and decide on some means of finding out more about Rayner and keeping an eye on him.  For that sort of work I should say that other Gaffney’s remarkably well cut out—­he’s a typical, sharp, knowing Cockney, with all his wits about him, and plenty of assurance.”

“It’s detective work, you know, Ambler,” said Allerdyke.  “It needs a bit of more than ordinary cuteness.”

“From my observation, I should say both those chaps are just cut for it,” answered Appleyard, with a laugh.  “What’s more, they enjoy it.  And when men enjoy what they’re doing—­”

“Why, they do it well,” agreed Allerdyke, finishing the sentence.  “Aye, that’s true enough.  All right—­I’ll speak to Gaffney, when I go back.  And look here—­as you’re so well known to this woman, Miss Slade or Mrs. Marlow, whichever her name is, you’d better not show up at the Waldorf at any time in my company, eh?”

“Of course,” said Appleyard.  “You trust me for that!  What we’ve got to do must be done as secretly as possible.”

Allerdyke rose to go, but turned before he reached the door.

“There’s one thing I’m uneasy about,” he said.  “If—­I say if, of course—­if these folks—­I mean the lot that’s behind this woman, for I can’t believe that she’s worked it all herself—­have got those jewels, won’t they want to clear out with them?  Isn’t delay dangerous?”