CHAPTER x.x.xII. OF THE YEAR, AND HOW MANY CIRCULATIONS MAKE UP THE GREAT YEAR OF EVERY PLANET.
The year of Saturn is completed when he has had his circulation in the s.p.a.ce of thirty solar years; of Jupiter in twelve; of Mars in two, of the sun in twelve months; in so many Mercury and Venus, the s.p.a.ces of their circulation being equal; of the moon in thirty days, in which time her course from her prime to her conjunction is finished. As to the great year, some make it to consist of eight years solar, some of nineteen, others of fifty-nine. Herac.l.i.tus, of eighteen thousand.
Diogenes, of three hundred and sixty-five such years as Herac.l.i.tus a.s.signs. Others there are who lengthen it to seven thousand seven hundred and seventy-seven years.
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 pa.s.sage 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-gla.s.s, 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 a.s.signs 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.
CHAPTER III. OF VIOLENT ERUPTION OF FIRE OUT OF THE CLOUDS. OF LIGHTNING. OF THUNDER. OF HURRICANES. OF WHIRLWINDS. Anaximander affirms that all these are produced by the wind after this manner: the wind being enclosed by condensed clouds, on account of its minuteness and lightness violently endeavors to make a pa.s.sage; and in breaking through the cloud gives noise; and the tearing the cloud, because of the blackness of it, gives a resplendent flame. Metrodorus, that when the wind falls upon a cloud whose densing firmly compacts it, by breaking the cloud it causeth a great noise, and by striking and rending the cloud it gives the flame; and in the swiftness of its motion, the sun imparting heat to it, it throws out the bolt. The weak declining of the thunderbolt ends in a violent tempest. Anaxagoras, that when heat and cold meet and are mixed together (that is, ethereal parts with airy), thereby a great noise of thunder is produced, and the color observed against the blackness of the cloud occasions the flashing of fire; the full and great splendor is lightning, the more enlarged and embodied fire becomes a whirlwind, the cloudiness of it gives the hurricane. The Stoics, that thunder is the clashing of clouds one upon another, the flash of lightning is their fiery inflammation; their more rapid splendor is the thunderbolt, the faint and weak the whirlwind.
Aristotle, that all these proceed from dry exhalations, which, if they meet with moist vapors, forcing their pa.s.sage, the breaking of them gives the noise of thunder; they, being very dry, take fire and make lightning; tempests and hurricanes arise from the plenitude of matter which each draw to themselves, the hotter parts attracted make the whirlwinds, the duller the tempests.
CHAPTER IV. OF CLOUDS, RAIN, SNOW, AND HAIL.
Anaximenes thinks that the air by being very much condensed clouds are formed; this air being more compacted, rain is compressed through it; when water in its falling down freezeth, then snow is generated; when it is encompa.s.sed with a moist air, it is hail. Metrodorus, that a cloud is composed of a watery exhalation carried into a higher place. Epicurus, that they are made of vapors; and that hail and snow are formed in a round figure, being in their long descent pressed upon by the circ.u.mambient air.
CHAPTER V. OF THE RAINBOW.
Those things which affect the air in the superior places of it are of two sorts. Some have a real subsistence, such are rain and hail; others not. Those which enjoy not a proper subsistence are only in appearance; of this sort is the rainbow. Thus the continent to us that sail seems to be in motion.
Plato says, that men admiring it feigned that it took origination from one Thaumas, which word signifies admiration. Homer sings:--
Jove paints the rainbow with a purple dye, Alluring man to cast his wandering eye.
(Iliad, xvii. 547.)
Others therefore fabled that the bow hath a head like a bull, by which it swallows up rivers.
But what is the cause of the rainbow? It is evident that what apparent things we see come to our eyes in right or in crooked lines, or by refraction: these are incorporeal and to sense obscure, but to reason they are obvious. Those which are seen in right lines are those which we see through the air or horn or transparent stones, for all the parts of these things are very fine and tenuous; but those which appear in crooked lines are in water, the thickness of the water presenting them bended to our sight. This is the reason that oars in themselves straight, when put into the sea, appear to us crooked. The third manner of our seeing is by refraction, and this is perspicuous in mirrors.
After this third sort the rainbow is affected. We conceive it is a moist exhalation converted into a cloud, and in a short s.p.a.ce it is dissolved into small and moist drops. The sun declining towards the west, it will necessarily follow that the whole bow is seen opposite to the sun; for the eye being directed to those drops receives a refraction, and by this means the bow is formed. The eye doth not consider the figure and form, but the color of these drops; the first of which colors is a shining red, the second a purple, the third is blue and green. Let us consider whether the reason of this red shining color be the splendor of the sun falling upon these small drops, the whole body of light being refracted, by which this bright red color is produced; the second part being troubled and the light languishing in the drops, the color becomes purple (for the purple is the faint red); but the third part, being more and more troubled, is changed into the green color. And this is proved by other effects of Nature; if any one shall put water in his mouth and spit it out so opposite to the sun, that its rays may be refracted on the drops, he shall see the resemblance of a rainbow; the same appears to men that are blear-eyed, when they fix their watery eyes upon a candle.
Anaximenes thinks the bow is thus formed; the sun casting its splendor upon a thick, black, and gross cloud, and the rays not being in a capacity to penetrate beyond the superficies. Anaxagoras, that, the solar rays being reflected from a condensed cloud, the sun being placed directly opposite to it forms the bow after the mode of the repercussion of a mirror; after the same manner he a.s.signs the natural cause of the Parhelia or mock-suns, which are often seen in Pontus. Metrodorus, that when the sun casts its splendor through a cloud, the cloud gives itself a blue, and the light a red color.
CHAPTER VI. OF METEORS WHICH RESEMBLE RODS, OR OF RODS.
These rods and the mock-suns are const.i.tuted of a double nature, a real subsistence, and a mere appearance;--of a real subsistence, because the clouds are the object of our eyes; of a mere appearance, for their proper color is not seen, but that which is advent.i.tious. The like affections, natural and advent.i.tious, in all such things do happen.
CHAPTER VII. OF WINDS.
Anaximander believes that wind is a fluid air, the sun putting into motion or melting the moist subtle parts of it. The Stoics, that all winds are a flowing air, and from the diversity of the regions whence they have their origin receive their denomination; as, from darkness and the west the western wind; from the sun and its rising the eastern; from the north the northern, and from the south the southern winds.
Metrodorus, that moist vapors heated by the sun are the cause of the impetuousness of violent winds. The Etesian, or those winds which annually commence about the rising of the Little Dog, the air about the northern pole being more compacted, blow violently following the sun when it returns from the summer solstice.
CHAPTER VIII. OF WINTER AND SUMMER.
Empedocles and the Stoics believe that winter is caused by the thickness of the air prevailing and mounting upwards; and summer by fire, it falling downwards.
This description being given by me of Meteors, or those things that are above us, I must pa.s.s to those things which are terrestrial.
CHAPTER IX. OF THE EARTH, WHAT IS ITS NATURE AND MAGNITUDE.
Thales and his followers say that there is but one earth. Hicetes the Pythagorean, that there are two earths, this and the Antichthon, or the earth opposite to it. The Stoics, that this earth is one, and that finite and limited. Xenophanes, that the earth, being compacted of fire and air, in its lowest parts hath laid a foundation in an infinite depth. Metrodorus, that the earth is mere sediment and dregs of water, as the sun is of the air.
CHAPTER X. OF THE FIGURE OF THE EARTH.
Thales, the Stoics, and their followers say that the earth is globular.
Anaximander, that it resembles a smooth stony pillar. Anaximenes, that it hath the shape of a table. Leucippus, of a drum. Democritus, that it is like a quoit externally, and hollow in the middle.
CHAPTER XI. OF THE SITE AND POSITION OF THE EARTH.
The disciples of Thales say that the earth is the centre of the universe. Xenophanes, that it is first, being rooted in the infinite s.p.a.ce. Philolaus the Pythagorean gives to fire the middle place, and this is the source fire of the universe; the second place to the Antichthon; the third to that earth which we inhabit, which is placed in opposition unto and whirled about the opposite,--which is the reason that those which inhabit that earth cannot be seen by us. Parmenides was the first that confined the habitable world to the two solst.i.tial (or temperate) zones.