Nevada desert. Here intrigues concerning a hidden gold mine provided
much excitement and peril, and the girls proved that, after all, a
fellow's sisters can be splendid companions in fun and hardship. An
exciting race with an express train, and the adventure of the "Human
Coyote," provided stirring times in this story, which also related the
queer antics of Professor Wandering William, an odd character indeed.
Space does not permit to relate their previous adventures in more
detail, but in "The Girl Aviators' Sky Cruise" still other interesting
and unusual experiences are described,--experiences that tested both
themselves and their machines in endurance flights.

Of Roy and Peggy's devoted friends, Jess and Jimsy Bancroft, it is
enough to say that both were children of Mr. Bancroft, a wealthy banker,
who had a palatial summer home near to the Prescotts' less pretentious
dwelling. Since we last met Jess and Jimsy their father had allowed them
to purchase an aëroplane known as the _White Flier_. It was in this
craft that Jimsy and Roy had flown over for mail when they made their
entrance at the beginning of this chapter. Of the letter they found
awaiting them we already know.

Jolly, good-natured Bess Marshall had taken up aviation as a lark. She
was a typical specimen of an American girl. Light-hearted, wholesome and
devoted to all sorts of sports, tennis, swimming, golf, motoring and
finally aviation had, in turn, claimed her attention.

And now, having introduced our heroes and heroines of the sky to those
who have not already met them, we will proceed to see how Miss Prescott
receives the startling plans that her young charges are about to lay
before her.