d body were attached. The
weight of this apparatus was some 24 lbs., and, launching himself on
it from a small eminence, as was done later by Lilienthal in his
experiments, the inventor made flights of over 120 feet. The glider in
question was exhibited at the Aeronautical Exhibition of 1868.

VI. THE AGE OF THE GIANTS

Until the Wright Brothers definitely solved the problem of flight and
virtually gave the aeroplane its present place in aeronautics, there
were three definite schools of experiment. The first of these was
that which sought to imitate nature by means of the ornithopter or
flapping-wing machines directly imitative of bird flight; the second
school was that which believed in the helicopter or lifting screw; the
third and eventually successful school is that which followed up the
principle enunciated by Cayley, that of opposing a plane surface to the
resistance of the air by supplying suitable motive power to drive it at
the requisite angle for support.

Engineering problems generally go to prove that too close an imitation
of nature in her forms of recipro-cating motion is not advantageous; it
is impossible to copy the minutiae of a bird's wing effectively, and the
bird in flight depends on the tiniest details of its feathers just as
much as on the general principle on which the whole wing is constructed.
Bird flight, however, has attracted many experimenters, including even
Lilienthal; among others may be mentioned F. W. Brearey, who invented
what he called the 'Pectoral cord,' which stored energy on each upstroke
of the artificial wing; E. P. Frost; Major R. Moore, and especially
Hureau de Villeneuve, a most enthusiastic student of this form of
flight, who began his experiments about 1865, and altogether designed
and made nearly 300 artificial birds, one of his later constructions
was a machine in bird form with a wing span of about 50 ft.; the
motive power for this was supplied by steam from a boiler which, being
stationary on the ground, was connected by a length of hose to the
machine. De Villeneuve, turning on steam for his first trial, obtained
sufficient power to make the wings beat very forcibly; with the inventor
on the machine the latter rose several feet into the air, whereupon de
Villeneuve grew nervous and turned off the steam supply. The machine
fell to the earth, breaking one of its wings, and it does not appear
that de Villeneuve troubled to reconstruct it. This experiment remains