projectile slowly across the shop--a task that would be impossible in a
motor of this size, if operated by electricity, gasoline, or any other
force at present in use. And, if this small motor will do that, I know
the large ones will send us through space to the moon. All ready, now."

Slowly the professor shoved over the lever, while Jack, Mark and the
others watched him carefully. They were standing back of him, in the
engine room of the projectile.

There was a clicking sound as the lever snapped into place. This was
succeeded by a buzzing hum, as the motor began to absorb the great
power from the red substance, which was not unlike radium in its
action. There was a trembling to the great projectile.

"She's moving!" cried Jack.

Hardly had he spoken when there was a flash of red fire, a sound as of
a bursting bomb, and everyone was knocked from his feet, over backward,
while Professor Roumann was hurled the entire length of the engine
room.

"The Cardite motor has exploded!" cried Mark. "Professor Roumann is
killed!"




CHAPTER V

THE WORK OF AN ENEMY