Is cold the mere privation of heat? 309. This is denied, for cold
seems to act on fluids and on solids: like heat or other actual
substances, it has a productive power, 310. Further, a mere privation
is not capable of degrees; but cold exists in different degrees,
310. A privation is nothing; cold is something, 311. A privation
is not the object of any of our senses; but cold can be felt,
311. Privation is something single and simple; substances have
differences, continually varying; and thus it is with cold, therefore
cold must be a substance, 312. Cold acts as a substance; it resists
heat, and overcomes it or is vanquished by it, 312. As there are four
elements, of which all things are composed, so there should be four
qualities, heat and cold, drought and moisture, 313. What sort of
substance is cold? 314. The air, when it becomes dark, becomes also
cold, 315. The freezing of water is caused by cold air, 316. Great
rivers and lakes are not frozen to the bottom, because the air does
not reach so far; the power of cold is therefore as many think, from
the air, 317; but this is doubtful, 318. Water makes things black;
air makes them white, 318. Oil is transparent because so much air is
in it, 318. It does not easily freeze, 319. Cold things are always
heavy, 319. Fire and water are opposites, 320. In winter, heat is
driven inward by cold, 321. It is driven downward from the surfaces
of great rivers, 321. Several considerations show that water, and
not air, is the cause of cold, 322. Water is cold of itself, being
the opposite of fire, 323. Opinion of Chrysippus combated, 324. The
earth, because it is dark, might be considered the cause of cold,
324, 325. But many hot things are dark, 326. Cold makes things hard,
heavy, rigid, and capable of resistance: the earth is therefore the
source of cold, 326, 327. Several considerations which seem to prove
that heat exists in every thing except the earth, and that cold
proceeds as a substance from the earth; which, and the whole subject,
in conclusion, is left in doubt, to be decided as the reader pleases.
327-330.