ents of this message were known. But when they send out an order
for a spy to do something, I have no doubt they use the most difficult
code they can devise, or at least one that they believe only the spy
will understand. So we may expect to catch messages in different codes
before we are through with our work."

Captain Hardy rose and began to look along the shelves of books. "Here
is a volume," he said presently, "that will tell us a great deal about
cipher messages."

He had just laid open the book when Roy rushed in from the wireless
room. "I've got another message," he said, holding out a paper on
which was a long string of letters.

"I wasn't expecting another message so soon," said Captain Hardy in
surprise. Slowly he read the letters on the paper Roy had given him:

"FTSTITEIAFTDLLTNSYWTORPSLHVNRLEEYLIOTEIH
UAOSEIEGGEVNCENDRRTERNRADSNLEEITOCGEOSHM."

"It looks like the same cipher used before," he went on. "If it is, we
can unravel this message without bothering the secret service. At any
rate we'll make a try at it. Where's that other message, Willie?"

The first message was brought. Captain Hardy spread it on the table
and the group bent over it.

"The letters divide evenly into four lines, you notice," said the
leader. "Let's see if this message will do the same."

He counted the letters with his pencil. "Eighty," he announced. "That
would make four lines of twenty letters each. We'll try it."

Rapidly he copied the first twenty letters. Below them he made a
second line of the next twenty letters. Then the third set of twenty
was written down. As he began the fourth row the three boys at his
side held their breath.

"He's got it," Willie Brown cried, as Captain Hardy wrote down the
first letter. "He's got it. It spells four."

Rapidly Captain Hardy finished out his line. The letters he had
written down read like this:

FTSTITEIAFTDLLTNSYWT
ORPSLHVNRLEEYLIOTEIH
UAOSEIEGGEVNCENDRRTE
RNRADSNLEEITOCGEOSHM

He picked up the paper and slowly spelled out the following message:

"Four--transports--sailed--this--evening--
Large--fleet--evidently--collecting--
No--destroyers--with--them."

For a moment there was complete silence. Then Henry spoke. "They can
see everything in Hoboken," he said. "It's a wonderful place to spy
from."

"That message didn't come from Hoboken," said Roy, who had been
listening to their conversation with one ear while he kept his