"There it goes! There it goes!" cried Mark, joyfully.

"Hurrah!" shouted Jack. "There she rises!"

"It suttinly am projectin' itself skyward!" yelled Washington, coming
from the dynamo.

Sure enough the cylinder was slowly rising in the air, bearing the
weight with it. It had lifted it clear from the ground and was
approaching the roof of the big shed.

"It will work! It will work!" exclaimed the professor, strangely
excited.

The next instant the cylinder, carrying the weight, sailed right out
of an open skylight, and began drifting outside the shop, and across
the fields.

"Quick! We must get it back!" cried Mr. Henderson. "If it gets away my
secret may be discovered and I will lose all! We must secure it!"

But the cylinder was now two hundred feet in the air and being blown
to the east, the weight dangling below it, making it look like a
miniature airship.

"We can never catch that!" cried Mark.

CHAPTER III

WASHINGTON DECIDES