drop his spade and grab the gun that was about his
neck.

Floating in the water above the diggers, were three immense sharks.
Their cruel mouths were partly open, showing three rows of big teeth,
and they were slowly turning over on their backs to make a sudden rush
and devour the men and boys. Owing to the peculiar shape of its maw a
shark can not bite until it turns over.

The professor motioned for Bill and Tom to move behind him, and
signalled for Jack, Mark and Andy to stand close with their weapons
ready.

The sharks floated lazily downward as if they knew they had the diggers
at their mercy. To run and escape was impossible, for no one could run
hampered by the weight of water and his diving suit.

One of the terrible fish opened its mouth wider and, with a flirt of its
tail aimed straight for the professor. Mr. Henderson raised his gun, and
took careful aim at the middle of the fish, half turned over. Unerringly
the electric bullet sped on its way. It entered the soft under part of
the shark, and immediately the thing struggled in its death agony.

The water was dyed with blood. At the same instant the other sharks
rushed forward in a swirl of foam. The boys and Andy fired as best they
could, and must have hit one of the creatures for there was a greater
commotion.

But the fight was not over. Instantly the ocean seemed alive with the
giant fish. Attracted by the blood of the killed ones, scores of the
tigers of the seas rushed toward the scene of combat making matters
livelier than ever.

The professor, the boys and Andy fired their guns at random. Redder and
more red became the water until their helmet lamps barely glowed in the
crimson sea. It seemed that a whole army of the voracious sharks had
attacked them.

The professor realized that to stay and attempt to fight all the sharks
in that part of the ocean was impossible. He motioned for the boys and
Andy to follow him. Then he slowly led the way back to the ship.

But the sharks were not to be gotten rid of so easily. Several of the
largest followed the diggers, their horrible eyes, and big mouths with
rows of cruel teeth, striking terror to the hearts of all.

One of the creatures made a rush for Bill and Tom who were close
together. Either or both of the men would have been bitten in twain, in
spite of the protection of their diving suits, had not Mark, with a snap
shot, killed the fierce fish.

It was now a running fight, and yet not so mu