THE
Practical Science Series
The following Vols. are now ready or in the Press:—
BALLOONS, AIRSHIPS, AND FLYING MACHINES. By Gertrude Bacon.
MOTORS AND MOTORING. By Professor Harry Spooner.
RADIUM. By Dr. Hampson.
METEOROLOGY; or, Weather Explained. By J. Gordon M‘Pherson, M.A., LL.D.
Others in Preparation
The Authoress, her Father, and Mr. Spencer
making an Ascent.
Frontispiece.
BALLOONS
AIRSHIPS AND FLYING
MACHINES
BY
GERTRUDE BACON