before she'll spark. I only wish I could get hold of some of the better
kind of metal."

The magneto of an aeroplane performs a service similar to one in an
automobile. It provides the spark that explodes the charge of gas in the
cylinders, and platinum is a metal, more valuable now than gold, much
used in the delicate parts of the magneto.

"Well, I guess it's walk for ours," said Ned ruefully.

"I'm afraid so," went on Tom. "If I only had some platinum, I could--"

"Perhaps I could be of service to you," suddenly spoke a voice behind
them, and turning, the youths saw a tall, bearded man, who had evidently
come from the lonely house. "Did I hear you say you needed some
platinum?" he asked. He spoke with a foreign accent, and Tom at once put
him down for a Russian.

"Yes, I need some for my magneto," began the young inventor.

"If you will kindly step up to my house, perhaps I can give you what you
want," went on the man. "My name is Ivan Petrofsky, and I have only
lately come to live here."

"I'm Tom Swift, of Shopton, and this is my chum, Ned Newton," replied
the young inventor, completing the introductions. He was wondering why
the man, who seemed a cultured gentleman, should live in such a lonely
place, and he was wondering too how he happened to have some platinum.

"Will that answer?" asked Mr. Petrofsky, when they had reached his