"What is it for?" asked Mark.

"To navigate the realm of the stars and moon!" cried the old man. "With
that I will rival the eagles in their flight!"

The boys were a little alarmed. The professor was strangely excited. His
eyes sparkled in the reflected light of the lamp. Jack and Mark thought
they might have been brought to the abode of a madman. They shrank back
a little. But they were reassured a moment later when, with a pleasant
laugh, the old man said:

"Don't be frightened, boys. I know what I am talking about. Here,
Washington, more light! We will show them what we have done, hidden away
from the sight of the curious, unbelieving world. Let them see my
_Monarch_!"

"We'll illuminationness dis abode like it was de orb ob day shinin'
heah!" exclaimed the negro, as he started several more lamps aglow.

"Are the shutters closed?" asked Mr. Henderson, anxiously.

"Tight as a drum-head," was the reply.

"Now look!" exclaimed the inventor, turning to the boys.

They were more than astonished at what they saw. They had no idea that
the rough shed held such a perfect piece of machinery.

Up near the roof of the place, which was quite high, there swayed an