though nothing like what it did higher up. And the ground was uneven. They had to cling to each other and it was very evident that no airship, not even the powerful Falcon, could have reached the place. Only an air glider would answer.
It took them half an hour to get to the opening of the ancient mine, and by that time it was nearly dark. But Tom had thought to bring electric torches, such as he had used in the underground city of gold, and they dispelled the gloom of the small cavern.
"Will you go in?" asked Ivan Petrofsky, when they had come to the place. He looked at Tom.
"Go in? Of course I'll go in!" cried our hero, stepping forward. The others followed. For some time they went on, and saw no traces of the precious metal. Then Ned uttered a cry, as he saw some dull, grayish particles imbedded in the earth walls of the shaft.
"Look!" he cried. Tom was at his chum's side in a moment.
"That's platinum!" cried the young inventor. "And of the very higest grade! But the lumps are very small."
"There are larger ones beyond," said the younger Russian brother.
Forward they pressed, and a moment later,
