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 highest grade! But the lumps are very small."
"There are larger ones beyond," said the younger Russian brother.
Forward they pressed, and a moment later coming around a turn in the cavern where some earth had fallen away, evidently recently, Tom could not repress a cry of joy. For there, in plain sight, were many large lumps of the valuable metal, in as pure a state as it is ever found. For it is always mixed with other metals or chemicals.
"Look at that!" cried Tom. "Look at that! Lumps as large as an egg!" and he dug some out with a small pick he had brought along, and stuffed them into his pocket.
"Bless my check book!" cried Mr. Damon, "and that stuff is as valuable as gold!"