ations experimented
somewhat, but in the main lagged behind these pioneers. Out of Spain
indeed came a most efficient craft--the Astra-Torres, of which the
British Government had the best example prior to the war, while both
France and Russia placed large orders with the builders. How many
finally went into service and what may have been their record are
facts veiled in the secrecy of wartime. Belgium and Italy both
produced dirigibles of distinctive character. The United States is
alone at the present moment in having contributed nothing to the
improvement of the dirigible balloon.

CHAPTER V

THE DEVELOPMENT OF THE AIRPLANE

The story of the development of the heavier-than-air machine--which
were called aeroplanes at first, but have been given the simpler
name of airplanes--is far shorter than that of the balloons. It is
really a record of achievement made since 1903 when the plane built
by Professor Langley of the Smithsonian Institution came to utter
disaster on the Potomac. In 1917, at the time of writing this book,
there are probably thirty distinct types of airplanes being
manufactured for commercial and military use, and not less than
fifty thousand are being used daily over the battlefields of Europe.
No invention save possibly the telephone and the automobile ever
attained so prodigious a development in so brief a time. Wise
observers hold that the demand for these machines is yet in its
infancy, and that when the end of the war shall lead manufacturers
and designers to turn their attention to the commercial value of the
airplane the flying craft will be as common in the air as the
automobiles at least on our country roads.

The idea of flying like a bird with wings, the idea basicly
underlying the airplane theory, is old enough--almost as old as the
first conception of the balloon, before hydrogen gas was discovered.
In an earlier chapter some account is given of early experiments
with wings. No progress was made along this line until the
hallucination that man could make any headway whatsoever against
gravity by flapping artificial wings was definitely abandoned. There
was more promise in the experiments made by Sir George Cayley, and
he was followed in the first half of the nineteenth century by half
a dozen British experimenters who were convinced that a series of
planes, presenting a fixed angle to the breeze and driven against it
by a sufficiently powerful motor, would develop a considerabl