quite so strikingly successful as the helicopter in the range of
flying machines, yet the essential weight increases so
disproportionately to the effective area that it is necessary to
go but very little beyond model dimensions for the helicopter to
become quite ineffective.

That is not to say that the lifting screw must be totally ruled
out so far as the construction of aircraft is concerned. Much
is still empirical, so far as this branch of aeronautics is
concerned, and consideration of the structural features of a
propeller goes to show that the relations of essential weight
and effective area do not altogether apply in practice as they
stand in theory. Paucton's dream, in some modified form, may yet
become reality--it is only so short a time ago as 1896 that Lord
Kelvin stated he had not the smallest molecule of faith in
aerial navigation, and since the whole history of flight
consists in proving the impossible possible, the helicopter may
yet challenge the propelled plane surface for aerial supremacy.

It does not appear that Paucton went beyond theory, nor is there
in his theory any advance toward practical flight--da Vinci
could have told him as much as he knew. He was followed by
Meerwein, who invented an apparatus apparently something between
a flapping wing machine and a glider, consisting of two wings,
which were to be operated by means of a rod; the venturesome one
who would fly by means of this apparatus had to lie in a
horizontal position beneath the wings to work the rod. Meerwein
deserves a place of mention, however, by reason of his
investigations into the amount of surface necessary to support a
given weight. Taking that weight at 200 pounds--which would