O THE WATER MAKE IT MORE COLD?

A GUEST, PLUTARCH, AND OTHERS.

I suppose you may remember that what Aristotle says in his problems, of
little stones and pieces of iron, how it hath been observed by some that
being thrown into the water they temper and cool it. This is no more
than barely asserted by him; but we will go farther and inquire into
the reason of it, the discovery of which will be a matter of difficulty.
Yes, says I, it will so, and it is much if we hit upon it; for do but
consider, first of all, do not you suppose that the air which comes in
from without cools the water? But now air has a great deal more power
and force, when it beats against stones and pieces of iron. For they do
not, like brazen and earthen vessels, suffer it to pass through; but, by
reason of their solid bulk, beat it back and reflect it into the water,
so that upon all parts the cold works very strongly. And hence it comes
to pass that rivers in the winter are colder than the sea, because the
cold air has a power over them, which by reason of its depth it has not
over the sea, where it is scattered without any reflection. But it is
probable that for another reason thinner waters may be made colder
by the air than thicker, because they are not so strong to resist its
force. Now whetstones and pebbles make the water thinner by drawing to
them all the mud and other grosser substances that be mixed with it,
that so by taking the strength from it may the more easily be wrought
upon by the cold. But besides, lead is naturally cold, as that which,
being dissolved in vinegar, makes the coldest of all poisons, called
white-lead; and stones, by reason of their density, raise cold in the
bottom of the water. For every stone is nothing else but a congealed
lump of frozen earth, though some more or less than others; and
therefore it is no absurdity to say that stones and lead, by reflecting
the air, increase the coldness of the water.

QUESTION VI

WHAT IS THE REASON THAT MEN PRESERVE SNOW BY COVERING IT WITH CHAFF AND
CLOTHS?

A GUEST, PLUTARCH.

Then the stranger, after he had made a little pause, said: Men in love
are ambitious to be in company with their sweethearts; when that is
denied them, they desire at least to talk of them. This is my case
in relation to snow; and, because I cannot have it at present, I am
desirous to learn the reason why it is commonly preserved by the hottest
things. For, when covered with chaff and cloth that