Welcome
   Home | Texts by category | | Quick Search:   
Authors
Works by Aristotle
Pages of Meteorology



Previous | Next
                  

Meteorology   


exhalation which accounts for its great quantity. Now since, as we

have said, the moist and the dry evaporations are mixed, some quantity

of this stuff must always be included in the clouds and the water that

are formed by condensation, and must redescend to the earth in rain.

This process must always go on with such regularity as the sublunary

world admits of. and it is the answer to the question how the sea

comes to be salt.

It also explains why rain that comes from the south, and the first

rains of autumn, are brackish. The south is the warmest of winds and

it blows from dry and hot regions. Hence it carries little moist

vapour and that is why it is hot. (It makes no difference even if this

is not its true character and it is originally a cold wind, for it

becomes warm on its way by incorporating with itself a great

quantity of dry evaporation from the places it passes over.) The north

wind, on the other hand, comb ing from moist regions, is full of

vapour and therefore cold. It is dry in our part of the world

because it drives the clouds away before it, but in the south it is

rainy; just as the south is a dry wind in Libya. So the south wind

charges the rain that falls with a great quantity of this stuff.

Autumn rain is brackish because the heaviest water must fall first; so

that that which contains the greatest quantity of this kind of earth

descends quickest.

This, too, is why the sea is warm. Everything that has been

exposed to fire contains heat potentially, as we see in the case of

lye and ashes and the dry and liquid excreta of animals. Indeed

those animals which are hottest in the belly have the hottest excreta.

The action of this cause is continually making the sea more salt,

but some part of its saltness is always being drawn up with the

sweet water. This is less than the sweet water in the same ratio in

which the salt and brackish element in rain is less than the sweet,

and so the saltness of the sea remains constant on the whole. Salt

water when it turns into vapour becomes sweet, and the vapour does not

Previous | Next
Site Search