But it was more with the ship’s ability to rise and descend that Professor Henderson was concerned, since on that depended their safety. So various tests were made, in generating the gas and using the negative gravity apparatus.
All worked to perfection. Obeying the slightest turn of the wheels and levers the Mermaid rose or fell. She stood still, suspended herself in the air, or rushed backward and forward.
Of course the machinery was new and did not operate as smoothly as it would later, but the professor and his friends were very well satisfied.
“Now we’ll try something new,” said the scientist to the two boys as they stood beside him in the tower. “I only hope this part succeeds, and we shall soon be off on our voyage.”
He turned several levers. There was a hissing sound as the gas rushed from the container, and the ship began to settle down.
“What’s th’ matter? Are we goin’ t’ hit th’ earth?” yelled Washington, rushing from the engine room.
“Keep quiet,” ordered the professor. “We are only going down, that’s all.”
“But good land! Perfesser!” exclaimed the colored man. “The ocean’s right under us! You forgot you sailed away from the island! We’ll be drowned suah!”
“Leave it to me,” said Mr. Henderson. “The Flying Mermaid is going to take a bath!”
“As long as it swims it will be all right,” observed Mark in a low tone to Jack. “I’m glad I can take care of myself in the water.”