350 BC

                                  METEOROLOGY

                                  by Aristotle

                          translated by E. W. Webster

                              Book I

                                 1

  WE have already discussed the first causes of nature, and all
natural motion, also the stars ordered in the motion of the heavens,
and the physical element-enumerating and specifying them and showing
how they change into one another-and becoming and perishing in
general. There remains for consideration a part of this inquiry
which all our predecessors called meteorology. It is concerned with
events that are natural, though their order is less perfect than
that of the first of the elements of bodies. They take place in the
region nearest to the motion of the stars. Such are the milky way, and
comets, and the movements of meteors. It studies also all the
affections we may call common to air and water, and the kinds and
parts of the earth and the affections of its parts. These throw
light on the causes of winds and earthquakes and all the
consequences the motions of these kinds and parts involve. Of these
things some puzzle us, while others admit of explanation in some
degree. Further, the inquiry is concerned with the falling of
thunderbolts and with whirlwinds and fire-winds, and further, the
recurrent affections produced in these same bodies by concretion. When
the inquiry into these matters is concluded let us consider what
account we can give, in accordance with the method we have followed,
of animals and plants, both generally and in detail. When that has
been done we may say that the whole of our original undertaking will
have been carried out.

  After this introduction let us begin by discussing our immediate
subject.

                                 2

  We have already laid down that there is one physical element which
makes up the system of the bodies that move in a circle, and besides
this four bodies owing their existence to the four principles, the
motion of these latter bodies being of two kinds: either from the
centre or to the centre. These four bodies are fire, air, water,
earth. Fire occupies the highest place among them all, earth the
lowest, and two elements correspond to these in their relation to
one another, air being nearest to fire, water to earth. The whole
world surrounding the earth, then, the affections of which are our
subject, is made up of these bodies. This world necessarily has a
certain continuity with the upper motions: consequently all its
power and order is derived from them. (For the originating principle
of all motion is the first cause. Besides, that clement is eternal and
its motion has no limit in space, but is always complete; whereas
all these other bodies have separate regions which limit one another.)
So we must treat fire and earth and the elements like them as the
material causes of the events in this world (meaning by material
what is subject and is affected), but must assign causality in the
sense of the originating principle of motion to the influence of the
eternally moving bodies.

                                 3

  Let us first recall our original principles and the distinctions
already drawn and then explain the 'milky way' and comets and the
other phenomena akin to these.

  Fire, air, water, earth, we assert, originate from one another,
and each of them exists potentially in each, as all things do that can
be resolved into a common and ultimate substrate.

  The first difficulty is raised by what is called the air. What are
we to take its nature to be in the world surrounding the earth? And
what is its position relatively to the other physical elements. (For
there is no question as to the relation of the bulk of the earth to
the size of the bodies which exist around it, since astronomical
demonstrations have by this time proved to us that it is actually
far smaller than some individual stars. As for the water, it is not
observed to exist collectively and separately, nor can it do so
apart from that volume of it which has its seat about the earth: the
sea, that is, and rivers, which we can see, and any subterranean water
that may be hidden from our observation.) The question is really about
that which lies between the earth and the nearest stars. Are we to
consider it to be one kind of body or more than one? And if more
than one, how many are there and what are the bounds of their regions?

  We have already described and characterized the first element, and
explained that the whole world of the upper motions is full of that
body.

  This is an opinion we are not alone in holding: it appears to be
an old assumption and one which men have held in the past, for the
word ether has long been used to denote that element. Anaxagoras, it
is true, seems to me to think that the word means the same as fire.
For he thought that the upper regions were full of fire, and that
men referred to those regions when they spoke of ether. In the
latter point he was right, for men seem to have assumed that a body
that was eternally in motion was also divine in nature; and, as such a
body was different from any of the terrestrial elements, they