"For the present I can only make surmises," Bell replied. "Van Sneck was
a slippery dog. Of course, he had found two of those plates. He kept the
one back so as to sell the other at a fancy price. My enemy discovered
this, and Van Sneck's sudden flight was his opportunity. He could afford
to get rid of me at an apparently dear rate. He stole Littimer's
engraving--in fact, he must have done so, or I should not have it at this
moment. Then he smudged out some imaginary spots on the other and hid it
in my luggage, knowing that it would be found. Also he knew that it would
be returned to Littimer, and that the stolen plate could be laid aside
and produced at some remote date as an original find. The find has been
mine, and it will go hard if I can't get to the bottom of the mystery
now. It is strange that your mysterious trouble and mine should be bound
up so closely together, but in the end it will simplify matters, for the
very reason that we are both on the hunt for the same man."

"Which man we have got to find, Bell."

"Granted. We will bait for him as one does for a wily old trout. The fly
shall be the Rembrandt, and you see he will rise to it in time. But
beyond this I have made one or two important discoveries to-day. We are
going to the house of the strange lady who owns 218 and 219, Brunswick
Square, and I shall be greatly mistaken if she does not prove to be an
old acquaintance of mine. There will be danger."

"You propose to go to-night?"

"I propose to go at once," Bell said. "Dark hours are always best for
dark business. Now, which is the nearest way to Longdean Grange?"