BOOK III.
In my two precedent treatises having in due order taken a compendious view and given an account of the celestial bodies, and of the moon which stands between them and the terrestrial, I must now convert my pen to discourse in this third book of Meteors, which are beings above the earth and below the moon, and are extended to the site and situation of the earth, which is supposed to be the centre of the sphere of this world; and from thence will I take my beginning.
CHAPTER I. OF THE GALAXY, OR THE MILKY WAY.
It is a cloudy circle, which continually appears in the air, and by reason of the whiteness of its colors is called the galaxy, or the milky way. Some of the Pythagoreans say that, when Phaeton set the world on fire, a star falling from its own place in its circular passage through the region caused an inflammation. Others say that originally it was the first course of the sun; others, that it is an image as in a looking-glass, occasioned by the sun's reflecting its beams towards the heavens, and this appears in the clouds and in the rainbow. Metrodorus, that it is merely the solar course, or the motion of the sun in its own circle. Parmenides, that the mixture of a thick and thin substance gives it a color which resembles milk. Anaxagoras, that the sun moving under the earth and not being able to enlighten every place, the shadow of the earth, being cast upon the part of the heavens, makes the galaxy. Democritus, that it is the splendor which ariseth from the coalition of many small bodies, which, being firmly united amongst themselves, do mutually enlighten one another. Aristotle, that it is the inflammation of dry, copious, and coherent vapor, by which the fiery mane, whose seat is beneath the aether and the planets, is produced. Posidonius, that it is a combination of fire, of finer substance than the stars, but denser than light.
CHAPTER II. OF COMETS AND SHOOTING FIRES, AND THOSE WHICH RESEMBLE BEAMS.
Some of the Pythagoreans say, that a comet is one of those stars which do not always appear, but after they have run through their determined course, they then rise and are visible to us. Others, that it is the reflection of our sight upon the sun, which gives the resemblance of comets much after the same manner as images are reflected in mirrors. Anaxagoras and Democritus, that two or more stars being in conjunction by their united light make a comet. Aristotle, that it is a fiery coalition of dry exhalations. Strato, that it is the light of the star darting through a thick cloud that hath invested it; this is seen in light shining through lanterns. Heraclides, native of Pontus, that it is a lofty cloud inflamed by a sublime fire. The like causes he assigns to the bearded comet, to those circles that are seen about the sun or stars, or those meteors which resemble pillars or beams, and all others which are of this kind. This way unanimously go all the Peripatetics, holding that these meteors, being formed by the clouds, do differ according to their various configurations. Epigenes, that a comet arises from a rising of spirit or wind, mixed with an earthy substance and set on fire. Boethus, that it is a phantasy presented to us by fiery air. Diogenes, that comets are stars. Anaxagoras, that those styled shooting stars descend from the aether like sparks, and therefore are soon extinguished. Metrodorus, that it is a forcible illapse of the sun upon clouds which makes them to sparkle as fire. Xenophanes, that all such fiery meteors are nothing else but the conglomeration of the enfired clouds, and the flashing motions of them.