It has all the power and characteristics of a powerful electrical battery, and can give a stunning shock to anybody which comes in contact with it.

All manner of fishes, large and small, even the monster whale, stand in dread of the torpedo.

It was a school of these odd fish which now proved the means of raising the siege.

They came down upon the school of swordfish with demoralizing effects.

In less time than it takes to tell it, every swordfish was far from the spot, and speeding for their lives to other depths.

Prof. Von Bulow saw the torpedoes coming and realized their nature.

He put his helmet against Frank’s and shouted:

“Look out! If those little fiends hit one of us they will knock the breath away.”

Frank aroused Captain Bell. Some loose planks were brought and the hatch covered.

This was to prevent the torpedoes from entering; but the latter did not seem at all inclined to attack the divers.