bullets straight into the open mouth
that was fringed with rows of the springy bone that is a part of a
whale's eating apparatus.

The shot took effect, and made a vital wound. In its death struggles the
beast lashed the ocean to foam, and, but for the fact that Andy as soon
as he fired the shot crouched down, pulling the others toward the floor
of ice, they might all have been killed.

The whale turned and made a rush in the opposite direction to that of
the divers. This was a welcome sign to the professor, for he knew the
animal was seeking open water and this told him it must be somewhere in
the vicinity.

Their hearts still beating loudly from the closeness of death, the
adventurers continued their way. On every side were fish, big and
little, and, though some of the larger ones thrust themselves to the men
and boys, as if wondering what strange creatures they were, none of them
offered to attack.

Led by the professor they made a complete circuit of the ship that was
held fast in the ice. As the inventor had surmised, the _Porpoise_ was
nipped only above and below. If she could be freed at either of those
points she could rise to the surface, or sink down under the ice.

After making a careful examination of the position of the craft, Mr.
Henderson motioned to have the dynamite placed on the ice, in front of,
and about two hundred feet away from the nose of the ship.

He connected the cartridges with the fuse and wires that were to explode
them, and then, taking the free end, he started back toward the ship.
Washington was on the watch for them, and operated the diving chamber.
Soon the four were back in the _Porpoise_.

"Now to see if our plan will work," said Mr. Henderson. "I am relying on
the well known downward force of dynamite to blow a hole in the bottom
part of the ice, so that we can drop below."

"Why not make a hole above so we can rise and escape?" asked Bill.

"Because," replied the professor, "we are now in the region of perpetual
ice. The ocean above us is one fast floe, or a number of smaller ones,
so that, in any event our progress would be impossible. But we can sail
far enough down under water to escape all the ice. That is the purpose
of the _Porpoise_. That is why I built her. We will now begin on the
last part of our voyage; that is if we can get free of the fearful grip
of this sea of ice."

There was little they could do to protect themselves. They would either
escape or be blow