Frank knew that the people wanted a demonstration of the Dart’s capabilities.
And he was willing to gratify them. He went into the pilot-house and the others went into the cabin.
Then Frank pulled the steel lever which opened the reservoir. Water displaced the compressed air.
Gracefully the Dart settled beneath the surface. Frank pressed a key and the electric lights blazed forth.
The bed of the river was as plainly revealed as in daylight.
For some while the Dart remained under the surface. Then it reappeared once more.
The people were satisfied. The air was rent with cheers, and it was a triumphal parting which the submarine travelers received.
Then the Dart glided away upon her course.
Down the river with great speed she went. In due course of time she reached the open sea.
The great trip through the Atlantic Valley was begun.