appeared in the doorway.
Jones' head lifted.

"It ought to be as--er--unique," he drawled, "as an--er--Ancient Roman
speaking perfect English."

Like a flash, the false Livius caught up the knife from the bench where
the false cobbler had dropped it and swung toward Average Jones. At
the moment the ample hand of Professor Warren, bunched into a highly
competent fist, flicked across and caught the assailant under the
ear. Enderby, alias Livius, fell as if smitten by a cestus. As his arm
touched the floor, Average Jones kicked unerringly at the wrist and the
knife flew and tinkled in a far corner. Bertram, with a bound, landed on
the fallen man's chest and pinned him.

"'Did he get you, Average?" he cried.

"Not--er--this time. Pretty good--er--team work," drawled the Ad-Visor.
"We've got our man for felonious assault, at least."

Enderby, panting under Bertram's solid knee, blinked and struggled.

"No use, Livius," said Average Jones. "Might as well quiet down and
confess. Ease up a little on him, Bert. Take a look at that scar of his
first though."

"Superficial cut treated with make-up paint; a clever job," pronounced
Bertram after a quick examination.

"As I supposed," said Average Jones.

"Let me in on the deal," pleaded Livius. "That letter is worth ten
thousand, twelve thousand, fifteen thousand dollars--anything you want
to ask, if you find the right purchaser. And you can't manage it without
me. Let me in."

"Thinks we're crooks, too?" remarked Average Jones. "Exactly what's in
this wonderful letter?"

"It's from Bacon to the author of the book, who wrote about 1610. Bacon
prophesies that Shakespeare, 'this vagabond and humble mummer' would
outshine and outlive in fame all the genius of his time. That's all I
could make out by loosening the stitches."

"Well, that is worth anything one could demand," said Warren in a
somewhat awed tone.

"Why didn't you get the letter when you were examining it at the auction
room?" inquired Average Jones.

"Some fool of a binder had overlooked the double cover, and sewed it in.
I noticed it at the auction, gummed the opening together while no
one was watching, and had gone to get cash to buy the book; but the
auctioneer put it up out of turn and old Graeme got it. Bring it to me
and I'll show you the 'pursed' cover. Many of the Percival books were
bound that way."

"We've never had it, nor seen it,"' replied Average Jones. "The
advertisement was only a trap