“All unmounted—­like that,” affirmed Allerdyke.  “And now, then, since it seems to be a matter of importance, I can tell you what James did with at any rate two of ’em.  He gave one to our cousin Grace—­Mrs. Henry Mallins—­a Bradford lady.  He gave another to a friend of my own, another amateur photographer, Wilson Firth—­gave him it in my presence at the Midland Hotel one day, when we were all three having a cigar together in the smoking-room there.  Wilson Firth’s a bit of a rival of mine in the amateur photographic line—­we each try to beat the other, you understand.  Now, then, James pulled one of these snapshots out and handed it over to Wilson with a laugh.  ‘There,’ he says, ’that’s our Marshall’s latest performance—­you’ll have a job to do aught better than that, Wilson, my lad,’ he says.  So that accounts for two.  And—­this is the third!”

“And the question, Mr. Allerdyke, the big question—­a most important question!—­is, how did it come into this man Lydenberg’s possession?” said the detective anxiously.  “If we can find that out—­”

“I’ve been thinking,” interrupted Allerdyke.  “There’s this about it, you know:  James and this Lydenberg came over together from Christiania to Hull in the Perisco.  They talked to one another—­that’s certain.  James may have given it to Lydenberg.  But the thing is—­is that likely?”

“No!” replied Chettle, with emphatic assurance.  “No, sir!  And I’ll tell you why.  If your cousin had given this photo to Lydenberg, as he might, of course, have given it to a mere passing acquaintance, because that acquaintance took a fancy to it, or something of that sort, Lydenberg would in all reasonable probability have just slipped in into his pocket-book, or put it loose amongst his letters and papers.  But, as we see, however Lydenberg became possessed of this photo, he took unusual pains and precautions about it.  You see, he cut it down, most carefully and neatly, to fit into the cover of his watch—­he took the trouble to carry it where no one else would see it, but where he could see it himself at a second’s notice—­he’d nothing to do but to snap open that cover.  No, sir, your cousin didn’t give that photo to Lydenberg.  That photo was sent to Lydenberg, Mr. Allerdyke—­sent!  And it was sent for one purpose only.  What?  That he should be able to identify Mr. James Allerdyke as soon as he set eyes on him!”

Allerdyke nodded his head—­in complete understanding and affirmation.  He was thinking the same thing—­thinking, too, that here was at least a clue, a real tangible clue.

“Aye!” he said.  “I agree with you.  Then, of course, the one and only thing to do is—­”