Now it has been shown that the enormous extent of wing required
to support a man of average weight would be much too large to be
flapped by man's arm muscles. But in this, as with everything
else, we have succeeded in harnessing the forces of nature into
our service as tools and machinery.

And is not this, after all, one of the chief, distinctions
between man and the lower orders of creation? The latter fulfil
most of their bodily requirements by muscular effort. If a horse
wants to get from one place to another it walks; man can go on
wheels. None of the lower animals makes a single tool to assist
it in the various means of sustaining life; but man puts on his
"thinking-cap", and invents useful machines and tools to enable
him to assist or dispense with muscular movement.

Thus we find that in aviation man has designed the propeller,
which, by its rapid revolutions derived from the motive power of
the aerial engine, cuts a spiral pathway through the air and
drives the light craft rapidly forward. The chief use of the
planes is for support to the machine, and the chief duty of the
pilot is to balance and steer the craft by the manipulation of
the rudder, elevation and warping controls.



CHAPTER XVIII
A Great British Inventor of Aeroplanes

Though, as we have seen, most of the early attempts at aerial
navigation were made by foreign engineers, yet we are proud to