"Sharks," was the reply, "these waters swarm with them."




CHAPTER V.

A TRAGEDY OF THE SKIES.


It was soon evident that the two men were supporting themselves in the
water. Their heads made black dots on the surface beneath which the
heavy deck structure of the dirigible had vanished. Through the
glasses it could be seen that they were swimming about awaiting the
arrival of the vessel which was rushing at her top speed to their aid.

Soon the Southern Cross was alongside and a dozen ropes and life buoys
were hastily cast over the side. But even as one of the men grasped a
rope's end he gave a scream of terror that long rang in the boys'
ears.

At the same instant a huge, dark body shot through the water and then
there was a whitish gleam as the monster shark turned on its back with
its jaws open displaying a triple row of saw-like teeth.

"Quick, shoot him," cried Captain Hazzard.

But nobody had a rifle or revolver. Frank hastily darted into his
cabin for his magazine weapon but when he reappeared there was only a