All water, when it hath been once hot, is afterwards more cold; as that which is prepared for kings, when it hath boiled a good while upon the fire, is afterwards put into a vessel set round with snow, and so made colder; just as we find our bodies more cool after we have bathed, because the body, after a short relaxation from heat, is rarefied and more porous, and therefore so much the more fitted to receive a larger quantity of air, which causes the alteration.
Therefore the water, when it is drawn out of the well, being first warmed in the air, grows presently cold.
Whereupon we began to commend the man very highly for his happy memory; but we called in question the pretended reason.

For if the air wherein the vessel hangs be cold, how, I pray, does it heat the water?
If hot, how does it afterwards make it cold?
For it is absurd to say, that the same thing is affected by the same thing with contrary qualities, no difference at all intervening.

While the gentleman held his peace, as not knowing what to say; there is no cause, said I, that we should raise any scruple concerning the nature of the air, forasmuch as we are ascertained by sense that it is cold, especially in the bottom of a well; and therefore we can never imagine that it should make the water hot.

But I should rather judge this to be the reason: the cold air, though it cannot cool the great quantity of water which is in the well, yet can easily cool each part of it, separate from the whole.
QUESTION V.WHAT IS THE REASON THAT PEBBLE STONES AND LEADEN BULLETS THROWN INTO 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.