"We are going through a cloud!" called the professor. So dense was the vapor that the boys, though within five feet of the captain, could not see him. His voice sounded far off.
Then came a sudden rush of light. The mist cleared away. The boys could see clearly, but as they glanced down they noticed rolling masses of white below them.
"We are above the clouds!" said the professor. "Be careful not to exert yourselves, as it is hard to breathe in this rarefied or thin atmosphere."
The boys experienced some difficulty, but by avoiding any exertion were not much bothered.
"Now we'll go down a bit," said the inventor, after the ship had whizzed along for several miles above the masses of vapor. "I want to get an idea where I am."
He turned some more wheels and levers. In a few minutes the ship was again surrounded with a white cloud. Then it passed away, and the earth came into view.
Suddenly the professor looked forward. He seemed to be gazing intently at something.
"I wonder what that is?" he muttered. He took down a telescope and adjusted it, peering forward with strained eyes.
"Can it be possible!" he exclaimed. Then he dropped the glass and frantically signaled to the engine room.
"We must look out for ourselves!" he cried, "Come here, Andy Sudds!"