D THEIR CAUSE
XLVI. ACCIDENTS AND THEIR CAUSE (Cont.)
XLVII. ACCIDENTS AND THEIR CAUSE (COnt.)
XLVIII. SOME TECHNICAL TERMS USED By AVIATORS
XLIX. THE FUTURE IN THE AIR

THE MASTERY OF THE AIR

PART I. BALLOONS AND AIR-SHIPS

CHAPTER I. Man's Duel with Nature

Of all man's great achievements none is, perhaps, more full of human
interest than are those concerned with flight. We regard ourselves
as remarkable beings, and our wonderful discoveries in science and
invention induce us to believe we are far and away the cleverest of all
the living creatures in the great scheme of Creation. And yet in
the matter of flight the birds beat us; what has taken us years of
education, and vast efforts of intelligence, foresight, and daring to
accomplish, is known by the tiny fledglings almost as soon as they come
into the world.

It is easy to see why the story of aviation is of such romantic
interest. Man has been exercising his ingenuity, and deliberately
pursuing a certain train of thought, in an attempt to harness the forces
of Nature and compel them to act in what seems to be the exact converse
of Nature's own arrangements.

One of the mysteries of Nature is known as the FORCE OF GRAVITY. It is
not our purpose in this book to go deeply into a study of gravitation;
we may content ourselves with the statement, first proved by Sir Isaac
Newton, that there is an invisible force which the Earth exerts on all
bodies, by which it attracts or draws them towards itself. This property
does not belong to the Earth alone, but to all matter--all matter
attracts all other matter. In discussing the problems of aviation we are
concerned mainly with the mutual attraction of The Earth and the bodies
on or near its surface; this is usually called TERRESTRIAL gravity.

It has been found that every body attracts very other body with a force
directly proportionate to its mass. Thus we see that, if every particle
in a mass exerts its attractive influence, the more particles a body
contains the greater will be the attraction. If a mass of iron be
dropped to the ground from the roof of a building at the same time as a
cork of similar size, the iron and the cork would, but for the retarding
effect of the air, fall to the ground together, but the iron would
strike the ground with much greater force than the cork. Briefly stated,
a body which contains twice as much matter as another is attracted
or drawn