Cossacks were on them.

In answer to a guttural command, he dropped the weapon and raised his
hands, as the professor had already done.

* * * * *

Two hours later, they were back at the rocket.

Led into the shack--which was furnished inside like an Oriental
hunting-lodge--they were confronted at once by Prince Krassnov.

Though his aristocratic features were immobile, it was obvious that he
was in no amiable frame of mind.

"So, my friends!" he exclaimed. "I leave you in India, and meet you
again in America, all within a matter of hours. It is but an example
of our modern progress, is it not?"

They made no reply.

"Ha! You are not sociable, after enjoying my hospitality, my
transportation? Then suppose we--as you Americans so quaintly
say--call a spade a spade! I gave you your chance. You declined it.
And what is the result? My beautiful Diamond Thunderbolt, my
immeasurable treasure, is buried forever."

"Through no fault of ours!" put in Stoddard.

"But buried nevertheless, and my adopted kingdom in revolt. Yet do not
think I mourn too much, my friends. Though the game is what you call
up, my plans shall go on. Here and elsewhere in the world, where we
have sub-headquarters, are billions of dollars' worth of
diamonds--supplies for years ahead. We shall not suffer. But
you--Professor Prescott and Doctor Stoddard--I have a very interesting
fate in store for you. How would you care to make a little scientific
expedition to Mars, say?"

"Mars?" gasped the professor.

"Yes, or Venus, or even Jupiter, not to mention the moon! Or how about
the sun? That would be an interesting sphere for exploration."

"We don't know what you're talking about," said Stoddard growing
nettled. "Why mince matters? Call a spade a spade, if you're going to!
What do you propose to do with us, now that you have us in your
power?"

The prince paused, drew forth a long Russian cigarette from an
exquisite platinum case.

"I propose," he smiled, when he had lit it, "to turn over my rocket to
you, my fellow scientists, since I shall have no further use for it
and it might be embarrassing to be found with it in my possession."

And the way he proposed to turn it over to them, as they had already
suspected, was to lock them in it and fire it off into space.

* * * * *

Within the hour, the man's diabolical plan had been put into
operation.

Led to the rocket, the l