woman coming in occasionally to clean. But I don't like these suspicious
characters hanging about.

"Who do you think they are?" asked Tom

"I'm almost afraid to think, but from my past experience I think--nay, I
fear--they may be spies, or agents of the Russian government"

"Spies!" cried Ned.

"Hush. Not so loud," cautioned Mr. Petrofsky. "They may even now be in
hiding, especially since your aeroplane landed so near my house. They
may see something suspicious even in that."

"But why should the Russian government set spies on you?" asked Tom in a
low voice.

"For two reasons. I am an escaped exile, and I am not a citizen of the
United States. Therefore I may be sent back to the sulphur mines. And
another reason is that they may think I know the secret of the platinum
treasure--the lost mine."

"Say this is getting interesting!" exclaimed Tom. "If we are going to
have a brush with some of the spies of the Russian government so much
the better. I'm ready for 'em!"

"So am I!" added Ned.

"You don't know them," said Mr. Petrofsky, and he could not repress a
shudder. "I hope they are not on my trail, but if they are--" he paused