flash of flame lit up the whole interior of the cave. It came from the copper switch.
"Something's wrong with the insulation!" cried Munson.
"Don't go near it!" yelled Folwell. "If you value your life, stand still!"
Hardly had he spoken than inside the cavern there sounded a report like that of a small cannon. A big ball of fire danced about the middle of the cave and then leaped on top of the steel box.
"This is a fearful storm," cried Munson.
The adventurers in the cave did not know what to say or do. They were in deadly peril.
Suddenly there came a crash louder tham any that had preceded it. The whole side of the cave where the switches were was a mass of bluish flame. Then came a ripping, tearing sound, and a tangle of wires and copper connections were thrown to the floor. At the same time the steel box, containing the materials from which diamonds were made, turned blue, and flames shot from it.
"It's all up with us!" cried Munson. "Run for it, everybody! The wires are down, and this place will be an electric furnace in another minute!"
He leaped toward the exit from the cave.
