cieties over
there, a society that works against the government. It says that Mr.
Petrofsky is being detained a prisoner in a lonely hut on the Atlantic
sea coast, not far from New York--Sandy Hook the letter says--and here
are the very directions how to get there!"

"No!" cried Ned, in disbelief. "How in the world could anybody in
Russia know that."

"It tells here," said Tom. "It's all explained. As soon as the secret
police got Mr. Petrofsky they communicated with the head officials in
St. Petersburg. You know nearly everyone is a spy over there, and the
letter says that Mr. Petrofsky's friends there soon heard the news, and
even about the exact place where he is being held."

"What are they holding him for?" asked Ned.

"That's explained, too. It seems they can't legally take him back until
certain papers are received from his former prison in Siberia, and
those are now on the way. His friends write to me to hasten and rescue
him."

"But how did they ever get your address?"

"That's easy, though you wouldn't think so. It seems, so the letter
explains, that as soon as Mr. Petrofsky got acquainted with us he wrote
to friends in St. Petersburg, giving my address, and telling them, in
case anything ever happened to him, to notify us. You see he suspected
that something might, after he found he was being shadowed that way.

"And it all worked out. As soon as his friends heard that he was
caught, and learned where he was being held, they wrote to me. Hurrah,
Ned! A clew at last! Now to wire the detective--no, hold on, we'll go
there and rescue him ourselves! We'll go in the airship, and pick up
Detective Trivett in New York."

"That's the stuff! I'm with you!"

"Bless my suspender buttons! So am I, whatever it is!" cried Mr. Damon,
entering the room at that moment.

CHAPTER VI

RESCUING MR. PETROFSKY

"We ought to be somewhere near the place now, Tom."

"I think we are, Ned. But you know I'm not going too close in this
airship."

"Bless my silk hat!" exclaimed Mr. Damon. "I hope we don't have to walk
very far in such a deserted country as this, Tom Swift."

"We'll have to walk a little way, Mr. Damon," replied the young
inventor. "If I go too close to the hut they'll see the airship, and as
those spies probably know that Mr. Petrofsky has been dealing with me,
They'd smell a rat at once, and run away, taking him with them, and
we'd have all our work to do over again."

"That's right," agreed