And thus opposing cold to heat, and dark to bright, he gives us to understand that black and cold are both of the same substance, as also are bright and hot. Now that black is proper to the water and not to the air, sense itself bears witness, nothing being darkened by the air, all things being clouded and blackened by water. So that if you throw the whitest wool that is, or a white garment into the water, it comes out black, and so remains, till the moisture be dried up again by the heat, or squeezed forth by presses or weights. Also when the ground is watered, the places that receive the drops grow black, the rest retaining their former color. And therefore the deepest waters, by reason of their quantity, always appear blackest, but the parts which are next the air afford a lovely and smiling brightness. But of all liquids, oil is the most transparent, because of the great quantity of air that is in it. And of this, the lightness of it is an unquestionable proof; the reason why it swims above all things, as carried upward by the air. Being poured forth upon the waves, it will cause calmness upon the sea, not because it is so slippery that the winds can have no power over it, as Aristotle thought, but because the waves will fall and sink when smitten by any moist body. And this is also peculiar to oil, that it shines and causes a transparency at the bottom of the water, while the watery humors are dispersed by the air. For being spurted out of the mouth into the sea, not only by those that sail in the night, but also by those that dive for sponges to the bottom of the sea, it will cast a light in the water. Water therefore has more of blackness than the air, but less of cold. Oil therefore, partaking more of air than most liquid things, is least cold, nor will it easily or suddenly freeze; for the air which is mixed with it will not suffer the congelation to grow hard. And therefore, as for needles, steel buckles, and such sort of small iron and steel wares, they never quench them in water but in oil, fearing lest the over-coldness of the water should make them too brittle. And indeed the truth is more truly enquired into from the consideration of these experiments, than those of colors. For hail, snow, and ice, as they are most transparent, so are most cold; and pitch, as it is hotter, so it is blacker and darker than honey.