ary."

So Cusack went off, and presently reappeared in the library with the
letter.

Riddell was busy at the moment searching through the catalogue, and
consequently let the letter lie unopened for some little time beside
him. In due time, however, he turned and took it up.

It was a strangely directed letter, at any rate--not in ordinary
handwriting, but in printed characters, evidently to disguise the
authorship.

Riddell hastily tore open the envelope of this mysterious missive and
read the contents, which were also written like printing, in characters
quite unrecognisable.

The letter was as follows:

"Riddel,--If you want to get to the bottom of that boat-race affair, you
had better see what Tom the boat-boy has to say. That's all."

CHAPTER TWENTY THREE.

TOM THE BOAT-BOY EARNS FOUR-AND-SIXPENCE.

Riddell, as he read over and over again the mysterious document in his
hand, hardly knew what to make of it.

It looked like a clue, certainly. But who had sent it? Was it a friend
or an enemy; and if the latter, might it not just as likely be a hoax as
not?

He examined the disguised writing letter for letter, but failed to
recognise in it the hand of any one he knew. He called back Cusack and
cross-examined him as to how and when the letter was brought to his
study; but Cusack could tell him nothing. All he knew was that when he
went in to look after Riddell's tea that afternoon, it was lying there
on the table. He couldn't say how long it had been there. He hadn't
been in the room since dinner, nor had Riddell.

Cusack was very curious to know what the letter was about concerning
which the captain seemed so much excited; but Riddell declined to
gratify him on this point, and put the paper away in his pocket and
returned to his work.

"No," said he to himself, "if it's a hoax there's no object in making it
public property, and still less reason if there's anything in it."

Of one thing he was determined--he must go down to-morrow morning and
have an interview with Tom the boat-boy. The thing _might_ all be a
hoax, but if there was the remotest chance of its being otherwise it was
clearly his duty to do what he could to find out the miscreant who had
brought such disgrace upon Willoughby. So he spent a somewhat uneasy
evening, and even appeared absent-minded when young Wyndham, now a
constant visitor to his study, paid his usual evening call.

"I say," said the boy, with beaming face, a