"News of my brother?"

"Of your brother! He is in a sulphur mine in the Altai Mountains, near the city of Abakansk."

"Where's that?" asked Tom for he had forgotten most of his Russian geography.

"The Altai Mountains are a range about the middle of Siberia," explained Mr. Petrofsky. "They begin at the Kirghiz Steppes, and run west. It is a wild and desolate place. I hope we can find poor Peter alive."

"And this city of Abakansk?" went on the young inventor.

"It is many miles from here, but I can give you a good map," said the Nihilist. "Some of our friends are there," he added with a half-growl. "I wish we could rescue all of them."

"We'd like to," spoke Tom. "But I fear it is impossible. But now that we have a clew, come on! Let's start at once! It may be dangerous to stay here. On to Siberia!"

CHAPTER XVIII

IN A RUSSIAN PRISON