Miss Prescott's home by an unscrupulous old banker, whose son was
the prime mover in the plots against Roy.

One of the means adopted to force him to sell his secrets was the
manipulation of a phantom aeroplane which, for a time, sadly puzzled
the lad and his sister. The mystery was solved in a strange way,
however, and almost at the same time, the baffling problem of what
had become of Mrs. Bancroft's jewels was also unraveled. All this
did not take place without many adventures being encountered by the
four chums. Among these was the encounter with the old hermit, Peter
Bell, who, through Peggy's agency, was restored to his brother,
James Bell, the millionaire western mining man.

James Bell became much interested in the Prescotts and their
aeroplanes. Finally he made an advantageous proposal to Roy to
travel West and operate for him a line of aeroplanes from some
desert mines he had discovered on a trip which almost cost him his
life. As autos could not cross the alkali, and transportation of
the product by wagons would have been prohibitive in cost, as well
as almost impossible to achieve, Mr. Bell had hit on the happy idea
of conveying the precious product of his property by aeroplane.

At the same time, it so happened that Mr. Bancroft, the father of
Jess and Jimsy, was summoned West by an important railroad deal.
This being the case, Jess and Jimsy at once set to work plotting how
they could gain their father's consent to their accompanying Peggy
and Roy. It was finally gained, although Mrs. Bancroft shook her
head over the matter, and, at first, would by no means hear of such
a thing. But Mr. Bancroft urged that it would be a good thing for
the children to see the great West, and that as Miss Prescott was to