He sat down at the table, laying his hand on the watch.
"After you left me this morning," he said, "I started puzzling and puzzling over what had been discovered, what had been done, whether there was more that I could do.

I kept thinking things over all the morning, and half the afternoon.

Then it suddenly struck me--there was one thing--that I'd never done and that ought to have been done--I don't know why I'd never thought of it till then--but I'd never had this photograph out of the watch.

And so I went back to the police-station and got the watch and opened it, and--look there, Mr.Allerdyke!" He had snapped open the case of the watch as he talked, and he now detached the photograph and turning it over, laid the reverse side down on the table by the postcard.
"Look at it!" he went on.

"Do you see ?--there's writing on it! You see what it says?
'This is J.A.Burn this when made use of.' You see?
And--it's the same handwriting as that on this card, making the appointment! Here, look at both for yourself--hold 'em closer to the light.