added.

"And mine, too," said Alexis Borious.

They started back early the next morning in a more terrific gale than
in any the glider had yet flown. But she proved herself a stanch craft,
and soon they were at the place where they had left the airship. It was
undisturbed.

Four days were spent in taking apart the glider and packing it on board
the Falcon. Then, with the platinum safely stored away Tom, with a last
look at the desolate land that had been so kind to them, sent his craft
on her homeward way.

It was when they were near the city of Pirtchina, on the Obi river,
that what might have proved a disastrous accident occurred. They were
flying along high, and at great speed, for Tom wanted to make all the
distance he could, to get out of Siberia the more quickly. They had had
a fair passage so far, and were congratulating themselves that they
would soon be in civilization again.

Suddenly, Mr. Damon, who had been on the after deck, taking
observations through a telescope, came running forward, crying out:

"Tom! Tom! What is that water dripping from the back part of the
airship?"

"Water?" exclaimed Tom. "No water is dripping from there."

"Come and look," advised Mr. Damon.

The young inventor raced back with him. He saw a thin, white stream
trickling down from the lower part of the craft. Tom sniffed the air
suspiciously.

"Gasolene! It's gasolene!" he cried. "We must have a leak in the supply
tanks!"

He dashed toward the reserve storeroom, and at that moment, with a
suddenness that was startling, the motor stopped and the Falcon lurched
toward the earth.

CHAPTER XXV

HOMEWARD BOUND--CONCLUSION

"All right!" yelled Ned, as soon as he heard Tom's cry. "I've got her
under control. We'll volplane down."

"Is it dangerous? Are we in danger?" asked Peter Petrofsky of his
brother, in Russian.

"I guess there's no danger, where Tom Swift's concerned," was the
answer. "I have not volplaned much, but it will be all right I think."

And it was, for with Ned Newton to guide the craft, while Tom did his
best to stop the leak, the craft came gently to earth on the outskirts
of a fairly large Siberian city. Almost instantly the Falcon was
surrounded by a curious throng.

"You had better keep inside," said Ivan Petrofsky to his brother and
Mr. Borious. "Descriptions of you are probably out broadcast by now,
but I am still sufficiently disguised, I think."

"But what is to be done?" demanded