The Flying Machine Boys on Duty
Reading edition
OR
The Clue Above the Clouds
By FRANK WALTON
AUTHOR OF
“The Flying Machine Boys on Secret Service”
“The Flying Machine Boys in the Wilds”
“The Flying Machine Boys in Mexico”
A. L. BURT COMPANY
NEW YORK.
Copyright 1913
By A. L. Burt Company
THE FLYING MACHINE BOYS ON DUTY
[3]THE FLYING MACHINE BOYS
ON DUTY