he extremities of its wings were made to flap, and the driving
power was obtained from a cylinder of compressed carbonic acid gas,
released through a hand-operated valve which, Lilienthal anticipated,
would keep the machine in the air for four minutes. There were certain
minor accidents to the mechanism, which delayed the trial flights, and
on the day that Lilienthal had determined to make his trial he made a
long gliding flight with a view to testing a new form of rudder that--as
Pilcher relates--was worked by movements of his head. His death came
about through the causes that Pilcher states; he fell from a height of
50 feet, breaking his spine, and the next day he died.

It may be said that Lilienthal accomplished as much as any one of the
great pioneers of flying. As brilliant in his conceptions as da Vinci
had been in his, and as conscientious a worker as Borelli, he laid the
foundations on which Pilcher, Chanute, and Professor Montgomery were
able to build to such good purpose. His book on bird flight, published
in 1889, with the authorship credited both to Otto and his brother
Gustav, is regarded as epoch-making; his gliding experiments are no less
entitled to this description.

In England Lilienthal's work was carried on by Percy Sinclair Pilcher,
who, born in 1866, completed six years' service in the British Navy
by the time that he was nineteen, and then went through a course of
engineering, subsequently joining Maxim in his experimental work. It was
not until 1895 that he began to build the first of the series of gliders
with which he earned his plane among the pioneers of flight. Probably
the best account of Pilcher's work is that given in the Aeronautical
Classics issued by the Royal Aeronautical Society, from which the
following account of Pilcher's work is mainly abstracted.[*]

[*] Aeronautical Classes, No. 5. Royal Aeronautical Society
publications.

The 'Bat,' as Pilcher named his first glider, was a monoplane which he
completed before he paid his visit to Lilienthal in 1895. Concerning
this Pilcher stated that he purposely finished his own machine before
going to see Lilienthal, so as to get the greatest advantage from any
original ideas he might have; he was not able to make any trials with
this machine, however, until after witnessing Lilienthal's experiments
and making several glides in the biplane glider which Lilienthal
constructed.

The wings of the 'Bat' formed a pronounced dihedral angle