"That's good; then we may be saved."
On they ran. They had no lanterns, but the blue light of the electricity, as it leaped from point to point inside the cave, where there were outcroppings of iron ore, made the place bright enough to see.
"Here we are!" cried Bill Renshaw at length. "Here's the way out!"
Making a sudden turn in the winding passage he showed the adventurers a small opening in the side of the crag. In an instant they had passed through, and found themselves in daylight once more. The sudden glare almost blinded them, for, though the sky was overcast by clouds, from which jagged tongues of lightning played, the outside was much lighter than the dark cave.
"I should say it was a storm!" cried Tom Swift. "See, it is striking every minute, and all around us!"
In fact, lightning bolts were falling on every side of the adventurers. Every time the balls of fire struck, they burst open great stones, or seared a livid scar on the face of some cliff. As for Tom and the others, they stood on a dry dirt hill, in which, fortunately, there was no iron ore. To this fact they undoubtedly owed their lives, though had there been rain, to mois-
