be given. Over and over again he rang out this number--forty
seven--the call for help.

"If Mr. Sharp only comes back he will hear that, even in
the house," thought poor Tom "Maybe Garret or Mrs. Baggert
will hear it, too, but they won't know what it means.
They'll think I'm just working on the submarine."

It seemed several hours to Tom that he pounded out that
cry for aid, but, as he afterward learned, it was only a
little over an hour. Signal after signal he sent vibrating
from the steel sides of the tank. When one arm tired he
would use the other. He grew weary, his head was aching, and
there was a ringing in his ears; a ringing that seemed as if
ten thousand bells were jangling out their peals, and he
could barely distinguish his own pounding.

Signal after signal he sounded. It was becoming like a
dream to him, when suddenly, as he paused for a rest, he
heard his name called faintly, as if far away.

"Tom! Tom! Where are you?"

It was the voice of Mr. Sharp. Then followed the tones of
the aged inventor.

"My poor boy! Tom, are you still alive?"

"Yes, dad! In the starboard tank!" the lad gasped out, and
then he lost his senses. When he revived he was lying on a