There was a brief instant of darkness.
Then Frank touched the electric lever and—presto! the interior of the boat was ablaze with light.
And outside the radiance shed far and wide into the sea depths. Myriads of fish came trooping down through the translucent mass.
They were of thousands of shapes, colors and varieties. Some of them were so large as to threaten the safety of the boat.
But fortunately these large ones were great cowards, and kept at a safe distance from the boat.
Frank turned on the searchlight and sent its rays shooting down into the depths.
As yet the bottom could not be seen.
“Are we getting down to the center of the earth?” cried Hartley; “it must be an immense depth here!”
“I see nothing of the bottom yet!” cried Clifford. “Can the little boat stand the strain, Frank?”
The young inventor knit his brows.