tween stems of dried fern
without being seen himself. He was looking into a deep green hollow,
bounded upon one side by an almost perpendicular wall of earth--a place
from which most likely sand had been dug a long time ago. At the foot
of the steep wall sat a man--the man whom they had been following. He
had a pencil in his hand, and a pocket-book on his knee, and he was
busily writing on a sheet of the pocket-book.

All this seemed innocent enough, but at the next moment the boys
looking on were filled with wonder. Albert suddenly laid down pencil
and pocket-book, bent forward, unlaced his left boot, and took it off.
Then he drew something from his pocket, and went to work on the heel of
his boot. The boys were not near enough to see what tool he was using,
but his movements were those of one who draws out screws, and they
clearly saw the heel of the boot come loose and fall into his hand.

Chippy gave his companion a nudge, and they looked at each other in
astonishment. Then they watched Albert closely, and saw him fold into
small compass the piece of paper upon which he had been writing, place
it inside the heel, and screw the latter up again.

An idea shot into Dick's mind. If he had never been a boy scout, that
idea would not have occurred to him; but in his enthusiasm he had
bought Baden-Powell's 'Aids to Scouting,' and read it over and over
again. One chapter in that little book now sprang to his memory, and
he touched Chippy, and beckoned to the latter to draw back completely
out of sight.

They slipped eight or ten yards away, and put their heads close
together and held a whispered conversation.

Dick's eyes shone brightly, and he took Chippy by the arm. 'Chippy,'
he said, 'I believe that's a spy!'

Chippy's sharp face wore a puzzled look. 'A spy!' he repeated. 'Wot's
he a-spyin' on in the he'th?'

'The fort, Chippy--the fort!' breathed Dick eagerly--'the Horseshoe,
the new fort!'

'Ah!' said the Raven, and began to see what his companion meant.

'I've read all about it in a book of B.-P.'s,' went on Dick.
'Foreigners will do anything to learn about a new fort. They send
spies to find out all they can. He's taking notes of all he discovers,
and hiding the papers in the heel of his boot.'

Chippy gave an eager nod. His keen face lighted up at this new and
wonderful turn of events. A spy! a foreign spy! He felt at once that
here was greater game than any escaped convict.

'That's wh