partly baked, and then they are put into the steel box. In some way terrific heat and pressure are applied, and the diamonds are made. But how the heat and pressure are obtained is what we have yet to learn."
He paused to watch the men at work. They were all busy, some attending to the machines, and others coming and going in and out of the cave. In one part a man was apparently getting ready a meal.
Suddenly there rushed into the cave a man who seemed much excited.
"Are you nearly ready with that stuff?" he cried. "There's a good storm gathering on the mountain!"
"Yes, we'll be ready in half an hour," answered one of the men at the mixing machine.
"Good. It will be flashing lightning bolts then, and we can see what luck we have. The last batch was a failure." The man hurried out again. Mr. Parker touched Tom and Mr. Jenks on their shoulders.
"What is it?" asked Tom.
"I know the secret of making the diamonds," said the scientist.
"What?" cried Mr. Jenks.
"It is by the awful power of the lightning bolts!" whispered Mr. Parker. "Everything is
