ver in it.'

'Righto,' said the Raven. 'I was just a-thinkin' 'ow to open it.'

Chippy went to work with the screw-driver in Dick's knife, and in two
minutes the heel-plate was off. The screws held the iron tip and a
single thickness of leather in place as a cover on the rest of the
heel. In the thickness of the heel was a small cavity out of which
fell three closely folded scraps of paper. The boys opened the papers
and looked at them. They could make nothing of the marks and signs
with which the tiny sheets were covered.

'There don't seem no sense at all here,' remarked Chippy.

'Those are secret signs,' replied Dick, 'so that no one can understand
the information except the people for whom it is meant. I expect
they'd know fast enough, if once they got hold of it.'

'Well, they won't 'ave it this time,' said Chippy. 'Wot are we goin'
to do wi' this?'

'I wonder where that sergeant is,' said Dick. 'I'll be bound that was
his business on the heath, Chippy--not trying to keep convicts in, but
trying to keep spies out.'

'I never took it in when he was tellin' us to tek' care o' the
convic's,' said Chippy. 'Not but wot I thought at fust as one of 'em
had got away.'

'So did I,' agreed Dick. 'I felt certain it was an escaped convict.'

'An' it wor' Albert,' murmured Chippy in wonder. 'Albert, wot 'ad been
bad, an' come down from Lunnon for his health,' and Chippy chuckled
dryly.

Before the papers were restored and the heel fastened up, Dick measured
the hidden cavity with his thumb-nail. It was one inch and a quarter
in length, one inch in breadth, and half an inch deep. 'Plenty of room
for a lot of dangerous information there,' remarked Dick.

'What makes 'em so sharp on this game?' asked Chippy.

'Oh,' cried Dick, 'I've heard about that. A spy gets a great sum of
money if he can carry back full information about the forts and
soldiers of another country. You see, it is a great help if you are
going to war with that country. You know just what you've got to meet,
and you can be ready to meet it.'

'I see,' said Chippy. 'Well, I've done the boot up again. Now we'll
have a look round for that sergeant. We've come straight back to the
part where we seed 'im afore.'

'So we have,' said Dick; 'there's Woody Knap right in front of us
again.'

'Hello! wot's that?' cried Chippy, whose eyes were always on the move.
He was pointing through the covert towards the direction from which
they ha