With which the young inventor went into the pilot-house and opened wide the pneumatic valve, which expelled the water from the tank.
This should cause the Dart to at once rise to the surface. But it did not.
It arose twenty feet or more, and then stopped with a jar. Frank was dumbfounded. What did it mean?
Again he opened the valve.
But it was of no use. The boat would not go up a single peg further. Here was a dilemma.
CHAPTER X.
BURIED UNDER THE SEA.
Frank Reade, Jr., was greatly puzzled at this very singular action of the pneumatic valve.
“What is the matter?” he exclaimed in sheer astonishment. “Something is wrong somewhere.”
He went hurriedly below and examined the electrical apparatus.
It seemed to be all right.