Chapter 19 ANOTHER CHALLENGE

"I know those fellows!" whispered Jack, as he and Andy came to a halt behind convenient trees.

"So do I. They are Mr. Strong's two crazy relatives, Bart Callax and Paul Shaff."

The cadets hardly knew what to do.

"I want that million dollars!" cried the man named Callax. "Give it to me!"

"And I want the order for an airship," put in Paul