Plutarch's Natural Questions (12-15)

Is it for that the winds, slipping the smooth oil, have no force, nor cause any waves? This may be probably said in respect of things external; but they say that divers take oil in their mouths, and when they spout it out they have light at the bottom, and it makes the water transparent; so that the slipping of the winds will not hold good here for an argument. Therefore it is to be considered, whether the sea, which is terrene and uneven, is not compacted and made smooth by the dense oil; and so the sea, being compact in itself, leaves passes, and a pellucidity penetrable by the sight. Or whether that the air, which is naturally mixed with the sea, is lucid, but by being troubled grows unequal and shady; and so by the oil’s density, smoothing its inequality, the sea recovers its evenness and pellucidity.

Is not that the cause which Theophrastus assigns,—that heat (to wit) shuns the cold, and is constrained by it on every side? Hence the waters are hottest in the bottom of the sea. And so it is on land; for springs are hotter in winter, and then lakes and rivers send up most vapors, because the heat is compelled to the bottom by the prevailing cold. Or it may be, nets do not rot at that time more than at another; but being frozen and dried in the cold, since they are therefore the more easily broken by the waves, they are liable to something like putrefaction

and rottenness. And they suffer most in the cold (as strained cords are aptest to break in such a season), because then there be most frequent storms at sea. Therefore fishermen guard their nets with certain tinctures, for fear they should break. Otherwise a net, neither tinged nor daubed with any thing, might more easily deceive the fish; since line is of an air color, and is not easily discerned in the sea.

Is it because hay rained upon is never well made? For the grass is cut down green and not dry, wherefore it putrefies when wet with rain water. But when before harvest it rains upon corn, this is a help to it against the hot south winds; which otherwise would not let the grain fill in the ear, but by their heat would hinder and destroy all coalition, unless by watering the earth there came a moisture to cool and moisten the ear.

Is it because a stronger grain needs more nourishment, and a weaker a light and thin one? Now barley is weaker and laxer than wheat, therefore it affords but little nourishment. And, as a farther testimony to this reason, wheat, that is ripe in three months, grows in dryer ground; because it is juiceless, and stands in need of less nourishment, and therefore is more easily brought to perfection.