Speculum mundi· Or A glasse representing the face of the world shewing both that it did begin, and must also end: the manner how, and time when, being largely examined. Whereunto is joyned an hexameron, or a serious discourse of the causes, continuance, and qualities of things in nature; occasioned as matter pertinent to the work done in the six dayes of the worlds creation.

Paragr. 1. Shewing that their first office is to shine upon the earth, to rule over the day and night, &c.

Artic. 1. Of light, what it is: and whether the Sunne be the onely fountain of light.

THe former part of my discourse hitherto in this dayes work, was chiefly founded upon these words, Let there be lights in the firmament of heaven; and upon these, And God made the starres also. But now I come to speak of their offices: The first whereof is that exquisite one above the rest; I mean their bright and radiant shining, by which the dismall clouds of foggie dark∣nesse are daintily devoured, and the sweet comelinesse of the worlds ornament made apparent. For without light all things would appeare like the face of hell or hor∣rour, and each parcell of the worlds fabrick lie buried in black obscuritie, & dismall squalour. Whereupon one speaketh worthily, saying, that amongst those * 1.1 qualities subject to sense, there is none more fit to shew the due decorum and comely beauty of the worlds brave stru∣cture, none more fit then light. For where it spreads it self (either above us, or below us) all things are then en∣compast with such a splendour, as if a golden garment were dilated over them, or curiously put upon them. Let it not then be ashamed to shine & shew it self to the praise of him who made it; For, Praise him sun and moon: praise him oh ye stars and light, was Davids song. But to proceed.

Authours make a difference between Lux and Lumen.

It is called Lux as it is in the fountain, that is, in a bodie which is lucid of it self; as in the sunne: so saith Zanchius. But it is Lumen as it is in some Medium, that is, in cor∣pore diaphano, as is the aire, or water. Lumen enim nihil aliud est quàm lux, lucisve imago, in corpore diaphano. From whence may be gathered, that that primarie light, which we comprehend under the name of Lux, is no other thing then the more noble part of that essence which is either in the sunne, moon, or starres: and so far as a corporeall substance may be given to fire, it may be also attributed to that which is properly called light; be∣ing in and of those lamps of heaven which were made ex primava luce chiefly, and so came to appeare of a fiery colour. Whereupon Patricius, writing against the Peri∣pateticks, saith, Lux est essentia stellarum. Nihil enim aliud flamma quàm lumen densius; & lumen, non aliud quàm flamma rarior. Calor quoque, non aliud quàm ignis rarefa∣ctus atque diffusus; & ignis, non aliud quàm calor densatus, sive lux compacta. Take therefore my meaning rightly, lest I be supposed to be much mistaken.

And again, concerning Radius, which is a Beam or Ray, it is no primarie light neither: but rather (as Patricius also writeth) it is Fulgor à Luce exiliens in rectam & acu∣tam figuram, seu in modum Pyramidis & Coni promicans. To which, Scaliger is affirming; saying, Lux est alia in cor∣pore lucido, ab eo non exiens; & alia à corpore lucis exiens, ut Lumen & Radius. And Zaharel also saith, Lux, alia est pro∣priè dicta in astris ipsis; alia, à luce producta in perspicuo. Whereupon I cannot but be perswaded, that light in it self, properly & primarily taken, must be an essentiall pro∣pertie; as formerly I have related: but to the aire, or other things enlightned by it, it is an * 1.2 accidentall quality ap∣proved of God as good, both to himself & the future crea∣tures. For although it be commonly said of compound things, that they are such as we may distinguish of them

in ipsam essentiam susceptricem, & in eam quae ipsi accidit qualitatem: yet here the case proves otherwise; because the sunne and starres have susceptam semel, secúmque immixtam lucem. And again (as saith Theodoret) Lucem quidem condidit ut voluit. Quemadmodum verò firma∣mento aquas divisit, ità lucem illam dividens ut voluit, lu∣minaria magna ac parva in coelo collocavit.

And as touching the brightnesse of the starres, the sunne may well be called Oculus mundi, The eye of the world. For he is indeed the chief fountain from whence the whole world receiveth lustre; shining alone, and enlightning our whole hemisphere, when all the other starres are hid. From whence some Philosophers and Astronomers have been of opinion that the fixed starres shine not but with a borrowed light from the sunne. Plutarch, in his 2 book and 17 chap. of the opinions of Philosophers, saith that Metrodorus, and his disciples the Epicures, have been of this minde. But according to the mindes of the best authours, and nearest equipage to truth, the starres are called lights, as well as the sunne and moon; although there be a difference between them, either of more or lesse. For Paul distinguisheth between* 1.3 the starres and sunne, non privatione lucis, sed tantùm gradu. And when God said, Let there be lights in the firmament of heaven, he made not the sunne alone, but the sunne, moon, and starres: the light in the starres be∣ing in very deed darkened by that in the sunne; which doth but differ in degree from that in them: Whereup∣on it is that the starres shew themselves by night onely when the sunne is hid, or in some deep pit whither the sunne-beams cannot pierce. If therefore we cannot see them, Id non solis, non stellarum culpâ fit, sed oculorum nostrorum hic est defectus: ob solaris enim luminis copiam ac vigorem debilitantur.

Also, some adde their influences; as that of the Little

dogge, the Pl•…•…iadas, and others, being plain testimonies of their native light: For if they had not their proper and p•…•…culiar light (being fo farre distant from the inferiour bodies) it is thought they could not alter them in such sort as they sometimes do: and evermore the further they be from the sunne, the better and brighter we see them.

And as for the diversitie of their influence, the differ∣ing qualitie of the subject causeth this diversitie. So that though this light, for the first three dayes, was but one in qualitie, it came to have divers effects as soon as it was taken and bestowed upon the starres and lights. And (perhaps) as there is in them the more of this fire, the •…•…otter is their qualitie: but little fire, and more water, the moister and cooler; and so also, the more earthy substance, the darker.

Neither do I think that we may altogether exempt* 1.4 the moon from her native light. For although she shi∣neth to us with a borrowed light, yet it is no conse∣quence to say, she hath therefore no own proper light. There is (saith Goclenius) a double light of the moon; Proper, and Strange. The Proper is that which is Homo∣geneall to it self, or lux congenita, a light begotten toge∣ther with the moon, and essentiall to it, although it be but weak. The other is that which it borroweth from the sunne; as is seen in eclipses & monethly revolutions: For she is one while full, another while hid; one while horned, another while half lightened; which is but in respect of us, who cannot see what light she borroweth, but as she approacheth from the sunne: for otherwise she is half lightened alwayes. Or (if you please) consi∣der it thus, that as a well polished Mirrour transporteth the light of the fire, or the sunne, against a wall or a floore; so the moon receiveth her light from the sunne, and reflecteth it in the night upon the earth: for the

sunne, being then absent, gives an abundant and free leave to see it. And again, as in a Mirrour, which hath behinde it his foil of lead scratched and torn, a man may perceive certain spots; So in the moon, because her bo∣die* 1.5 is in some places rare and transparent, and in other places massie, thick, and solid, there appeare certain Maculae or blemishes: for those places and parts are not of a fit temper to reflect the light of the sunne.

But if it be so in the moon, why may not the other starres shine likewise with a borrowed light as well as she?

I answer, Because we have not the like reasons to de∣clare it. Neither is it like (saith Patricius) that that un∣measurable companie of fixed starres in the highest part of heaven (which is so much more noble then the place of the sunne, by how much it comes nearer to the Hea∣ven of heavens) should shine but by the light of the sunne: For neither in them, nor in any other of the Pla∣nets, doth any man see a waxing and waning of light; nor yet are they ever eclipsed, but shew alwayes of one and the same brightnesse: and therefore it is not the same reason between the moon and them. Perhaps, if their bodies were composed in the same manner with the bodie of the moon, or had the like proportions and tem∣peraments that she hath, it might be so▪ but her lownesse shews her gravitie; and her gravitie her soliditie; and her soliditie shews, not onely her own light to be weak through a want of that fierie matter, or lux primaeva, which is in the other starres in a differing degree, but also her aptnesse for reflexion is declared to be such, as she may well shine by a borrowed light.

Howbeit I do also think that the starres have aliquid lucis alienae, which they receive from the sunne. To which Patricius also assenteth (as he is mentioned by * 1.6 Casman in the first part of his Astrologie) saying, Tri∣buit

quidem omnibus, sed lucere nequaquam facit. Nam & ipsa flammae sunt, & suâ essentiâ lux sunt, non minùs & suis viribus lucere possunt, & lucent. Sed lumen suum eis sol addit, lucémque eorum reddit lucidiorem. Lucem ergò eis non indit, sed insitam adauget: meaning that the sunnes light inereaseth the light of the starres, making it the brighter and the clearer: which must be understood of them, so long as they are at a convenient distance from the sunne. For if they be too neare, either the lesser light is obscured by the greater (as is seen in the Planets, being often hid by the beams of the sunne) or else such a dark starre as Mercurie, will with the losse of his light shew us his dark bodie, which sometimes happeneth, being then seen as a spot in the sunne: For if you take Mercu∣rie in his best hue, he hath but a cloudie countenance, and a leaden look; which therefore argueth that he hath a thick bodie and little light: of which I shall need to say no more.

Artic. 2. Of the twinkling of starres, or vibration of their light.

THe twinkling of the starres is the vibration or trem∣bling of their light. Or rather thus; It is when the light of any starre seemeth to tremble. For indeed, to speak properly, the starres themselves do not twinkle, as we think they do; but either from the trembling of the eye, or motion of the aire, this appearance proceed∣eth. For when the eye looks long at a sensible object whose brightnesse excelleth the sense, it then beginneth to faint, and being weak and wearie, is possessed with a kinde of trembling; and thereupon we think that the starre it self twinkleth. Also the Optick Masters confesse and prove, that the forms of the starres are compre∣hended

of the sight reflectly, and not rightly: that is, a right line drawn from the eye falleth not into the centre of the starre, but into the form of it reflected and re∣fracted in the aire to the sight. Now it is manifest, that as the aire hath one motion proper to it, which is up∣wards; so hath it another motion improper, caused by the revolution of the heavens every 24 houres, which draweth all the airie region about therewith: by which means the apparent form of the starres is distracted, seeming to cast forth sparkles, called twinkling. For if the bodie move wherein the form of the starre appear∣eth, it must be so: which we may well prove by a piece of silver in the bottome of a swift running brook, or by the reflexion of the starres seen in the same: for by the running of the water the reflected form is distracted, and as it were broken: and so it is likewise in the aire with the starres.

But may not this twinkling be seen in the Planets as well as in the other starres? I answer, that not alwayes, yet sometimes it may: and this is but when a watrie va∣pour is neare unto them, which is carried and tossed of the windes with a various motion: for then the forms of the Planets also being refracted in the said vapour, ap∣peare to the sight as if they twinkled. Now this is most of all perceived in the East at the time of their rising: whereupon it comes to passe that the common people* 1.7 have supposed they have sometimes seen the sunne dance, and as it were hop up and down; which, why some have attributed it to such and such dayes, is * 1.8 fabu∣lous: For this may be upon any day when the sunne meets with a fit portion of vapours at the time of his rising; and the other Planets may also in some sort sometimes shew it, when they have climbed to an in∣different height above the Horizon: which because it is not ordinarie, some have falsely supposed that the Pla∣nets

twinkle not at all. And again, let this be remem∣bred, that (if there be fit vapours rightly placed) Mars and Venus twinkle more then Saturn, Jupiter, and Mer∣cury: but otherwise this appearance is neither in Mars nor Venus, nor any of the rest.

Notes

• * 1.1

  But how it is a qualitie see afterwards.
• * 1.2

  Observe this difference: be∣cause light com∣monly taken is said to be a qualitie.
• * 1.3

  1. Cor. 15. 41.
• * 1.4

  The ☽
• * 1.5

  The Macul•…•… l•…•….
• * 1.6

  Cap. 10. quest. 7.
• * 1.7

  A reason of the Sunnes dancing.
• * 1.8

  See Seal. Exer. 63. & Goclenius Disput. Phys.