Thrasimene, as stated, or a mere hop with an ineffectual glider
may have grown with the years to a legend of gliding flight. So
far, too, there is no evidence of the study that the conquest of
the air demanded; such men as made experiments either launched
themselves in the air from some height with made-up wings or
other apparatus, and paid the penalty, or else constructed some
form of machine which would not leave the earth, and then gave
up. Each man followed his own way, and there was no
attempt--without the printing press and the dissemination of
knowledge there was little possibility of attempt--on the part
of any one to benefit by the failures of others.

Legend and doubtful history carries up to the fifteenth century,
and then came Leonardo da Vinci, first student of flight whose
work endures to the present day. The world knows da Vinci as
artist; his age knew him as architect, engineer, artist, and
scientist in an age when science was a single study, comprising
all knowledge from mathematics to medicine. He was, of course,
in league with the devil, for in no other way could his range of
knowledge and observation be explained by his contemporaries; he
left a Treatise on the Flight of Birds in which are statements
and deductions that had to be rediscovered when the Treatise had
been forgotten--da Vinci anticipated modern knowledge as Plato
anticipated modern thought, and blazed the first broad trail
toward flight.

One Cuperus, who wrote a Treatise on the Excellence of Man,
asserted that da Vinci translated his theories into practice,
and actually flew, but the statement is unsupported. That he
made models, especially on the helicopter principle, is past