table. "That's the truth. This has been
reproduced from mine, d'ye see? Look here--happen you don't know much
about photography, but you'll follow me--I always use a certain sort of
printing-out paper; I've stuck to one particular sort for years--all the
photos in that album are done on that particular sort. The four prints I
made of James's last photo were done on that paper. Now then--this photo,
this print that you found in Lydenberg's watch, is not done on that
paper--it's a totally different paper. Therefore--this is a reproduction!
It is not my original print at all--it's been copied from it. See?"

Chettle, who had followed all this with concentrated attention, nodded
his head several times.

"Clever--clever--clever!" he said with undisguised admiration. "Clever,
indeed! That's a smart bit of work, sir. I see--I understand! Bless my
soul! And what do you gather from that, Mr. Allerdyke?"

"This!" answered Allerdyke. "Just now, Mrs. Marlow said to me, speaking
of her photo--the fourth print, you know--'I misplaced it some time
ago,' she said, 'and couldn't lay hands on it, but I came across it
accidentally this morning.' Now then, Chettle, here's the thing--somebody
took that fourth print from Mrs. Marlow, reproduced it--and that--that
print which you found in Lydenberg's watch is the reproduction!"

"So that," began Chettle suggestively, "so that--"

"So that the thing now is to find who it is that made the reproduction,"
said Allerdyke. "When we've found him--or her--I reckon we shall have
found the man who's at the heart of all this. Leave that to me! Keep this
a dead secret until I tell you to speak--we shall have to tell all this,
and a bonny sight more, to your bosses at headquarters--off you go to
Hull, and do what you have to do, and I'll get on with my work here. I
said I didn't know whether this discovery makes things thicker or
clearer, but, by George, it's a step forward anyway!"

Chettle put the reproduction back into the case of the watch and bestowed
it safely in his pocket.

"One step forward's a good deal in a case like this, Mr. Allerdyke," he
said. "What are you going to do about the next step, now?"

"Try to find out who made that reproduction," replied Allerdyke bluntly.
"No easy job, either! The ground's continually shifting and changing
under one's very feet. But I don't mind telling you my present
theory--somebody's got information of that jewel deal from Fullaway's
office, somebod