Page:Cyclopaedia, Chambers - Volume 1.djvu/631

 EAR

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EAR

one twinkling of an Eye, muft fly 8222 ; Jupiter 28688 5 and Saturn 52060 Miles. Laftly, the fix'd Stars being yet vafdy more remote from the Earth than Saturn, their Mo- tion in, or near the Equator, mufti be vaftly fwifter than that of Saturn.

9. If the Earth be at Reft, and the Stars move by any common Motion, the feveral Planets muft each Day defcribe feveral Spirals running forth to a certain Term towards the North, and thence returning to the opposite Term towards the South ; fometimes narrower, and fometimes broader.

For the Diftances of the feveral Planets from the Zenith alter every Day 5 increasing to a certain Point towards the North, and thence decreaiing again towards the South : Consequently, the Altitude of the Pole, being always found the fame, and the Planets not returning to the fame Point of the Meridian j they do not defcribe Circles but Spirals. Add, that as the feveral Planets do not retain the fame Diftance from the Earth, but arc fometimes nearer, and fometimes recede further from it 5 at a greater Diftance, a greater Spiral, and at a lefs, a lefs is described.

Further, as their Motion is flower, when the Planet is further from the Earth 5 the greater Spirals are defcribed in lefler Times than the letter. And as the greateft and leaft Diftance of the Planets from the Earth is not affix'd to the fame Point of the Heavens, the Planets have moved in different Tracts every Day from the Beginning.

10. Bodies let fall from any considerable Height, are four.d by Experiment not to fall upon the Spot perpendi- cularly under them, but to the South-Eaft thereof. See Descent.

The Experiment was propofed to Dr. Hook, in the Year 1679, by a Perfon, who fuggefted, that if the Earth had any diurnal Motion, the Body would fill to the Eaft of the perpendicular. Dr. Hook, on that Occasion, read a Dif- eourfe before the Royal Society, wherein he endeavoured, a priori, to affign what Curve a falling Body would describe ; aflerting particularly, that the Fall of the Body would not be directly Eaft, but South Eaft : Which was confirmed by divers actual Trials.

11. The Power of Gravity is found to decreafe as you approach nearer to the Equator : Which is a Circumftance that agrees to all Bodies, which have a Motion on their Axis; and them only, as being really the neccflary Rcfult of fuch Motions. See Gravity.

For a Body, revolving on its Axis, the Parts, or Appen- dages thereoi, are continually endeavouring ro recede trom the Centre. Confequently, the Equator being a great Circle, and the Parallels all decreaiing towards the Poles, the Cen- trifugal Force is greateft in the Equator, and decreafes to- wards the Poles, in the Ratio of the Diameters of the Parallels to that of the Equator. Now the Power of Gravity determines the feveral Parts or Appendages towards the Centre ot the whole : Confequently the Centrifugal Force acting contrary to the Power of Gravity, retards the Defcent of Bodies, and that moll where it is greateft.

Dr. Keil computes, that the Force of Gravity to the Centrifugal Force at the Equator is- as 289 to 1 ; confe- quently, a Body placed there, would lofe one 289 th Part of the Weight it would have, were the Earth at Reft. Confe- quently, the Centrifugal Force, at the Poles, being infinitely imall, a Body will there weigh 289 Pounds, which at the Equator only weighs 288.

12. The following is an actual Demonstration of the Earths Motion, drawn from Phyfical Caufes, for which we are indebted to the Difcoveries of Sir Ijaac Newton ; and which Dr. Keil takes for conclufive, and unanfwerable.

All the Planets, 'tis demonftrated, gravitate towards the Sun : And Obfervations teftify to us, either that the Earth turns round the Sun, or the Sun round the Earth, in fuch Manner, as to defcribe equal, Areas in equal Times. But 'tis demonftrated further, that whenever Bodies turn round each other, and regulate their Motion by fuch Law, the one muft of Neceflity gravitate to the other : Confe- quently, if the Sun in its Motion do gravitate to the Earth 5 Action or Re-action being equal and contrary, the Earth muft like wife gravitate towards the Sun. Again, the fame Author has demonftrated, that when two Bodies gravitate to one another, without directly approaching one another in right Lines 5 they muft both of them turn round their common Centre of Gravity : The Sun and Earthy therefore, do both turn round their common Centre ot Gravity 5 but the Sun is fo great a Body in Refpect of our Earth, which is, as it were, but a Point 5 that the common Centre of Gravity of the two Bodies, will lie within the Body of the Sun it felf, and not far from the Centre of the Sun. The Earth, therefore, turns round a Point, which is in the Body of the Sun ; and therefore turns round the Sun. Q.E.D.

To fay no more, to fuppofe the Earth at Reft, con- founds and deftroys all the Order and Harmony of the Univerfe, annuls its Laws, and fets every Part at Variance

with other, robs the Creator of half the Praife of his Work, and Mankind of the Pleafure of the Contemplation thereof. In Effect, it renders the Motions of the Planets in- extricable and ufelefs, which otherwife are plain and fimple. £0 that fuch of the later Aftronomers, as have afferted ic with the moft Zeal, have been forced to fct it afide., when they came to compute the Motions of the Planets. None of them would ever attempt to compute thefe Motions iri variable Spirals ; but in all their Theories they tacitly fup- pofe the Earth to move on its Axis, fo as to turn the diurnal Spirals into Circles.

Thus, the Jefuite Ricciolus, who, at the Pope's Com- mand, opppofed the Motion of the Earth with all his Might, as fomething contrary to Holy Scripture 5 yet, to frame Agronomical Tables, which fliould any thing tolerably agree to Obfervation, he was forced to have Recourfe to the Motion of the Earth, as his only Refuge.

This, 2)e Chafes, another of the fame Fraternity, frankly

confefTcs : ' fp. Ricciolus nullas "Jfabulas aptare potuit

1 qua vel mediocriter Obfervationibus refponderent 5 Nifi 1 ficsndum Syftema terra mot£ 5 notwithstanding, that he 1 called in all the foreign and forced Aififtances of move- 4 where _ he undertakes to give accurate Tables of the ' Ccelcftial Motions, he gives in to the Hypothecs of the ' Motion of the Earth: 2)e Chales Mron. Reformat.
 * able Epicycles : So that in his Jftronomia reformata y

z.x. a 1.

The Syftcm, then, which fuppofes the Earth at Reft, Isj of it felf, of no Ufe, or Significancy in Aftronomy 5 Nor does it avail more in Phyficks : for the principal Pheno- mena are no Way deducible from it - 7 bur the Retainers thereto are either forced to fly to the immediate Agency of the Deity, (which in Phyficks is the fame as the Re- duEiio ad Jbfardum in Geometry) or to Reafons and Principles unknown.

Some oppofe the Motion of the Earth, as contrary to Revelation ; there being mention made, in Holy Scripture, of the Sun's riling and fating $ of his ftanding ftill in the Time of JoJJjua $ and his going back in that of He- zekinh.

Now, to take the genuine Seme of thefe Paffages, the Laws of Interpretation muft be fettkd. 1. Then, we fup- pofe, that the feveral Words of Scripture have their feveral Ideas correfponding to them 5 and that a Man takes their Scnfe, in whom thofe Ideas are excited by the reading. 2. That the Words of Scripture, attentively read, are fut- ficient to excite thole Ideas in a Mind not prcpoftefs'd. Flence, 5. It iollows, that either God muft have exhibited the Definitions of the Words that occur in Scripture 5 or, that he fuppofes prior Notions, and leaves us to take their Senfe the ordinary Way. Hence, 4. We argue, that no other Ideas are to be affix'd to the Words of Scripture, but fuch as occur to a Perfon who looks or attends to the Things 'emfelves fpoke of. See Definition.

By the Swns Rifting-, therefore, is meant no more than his Re-appearance in the Horizon, after he had b:en hid below it: And by his Setting, an Occultation of the Sun, before vifible in the Horizon. When the Preacher therefore fays, Ecc/ef. I. 5. T" he Sun rifes, and fets, and returns to hh 'Place ; he means, doubdefs, no more than the Sun, which before was hid, is now feen in the Horizon 5 and after being there confpicuous, is hid again, and at length, re-appears in the Eaft. For thus much only appears to a Perfon who views the Sun 5 and therefore thus much, and no more, is cxprefs'd by the facred Writers.

In like Manner, when in Jop.'K. 12, 13. the Sun and Moon are faid to have food ftill ; all meant by Station is, that they did not change their Place, with Refpect to the Earth. For that General, by Sun ft and thou ftill over Gibeon, and thou Moon, over the Valley of Ajalon 5 required no more, than that the Sun, which then appeared over that City, ihould not change its Situation. And from his bidding the Sun to keep his Situation, it would be un- juft to infer, that it moves round the Earth at Reft.

Gaffendzis, very pertinently to the prefent Puipofe, di- ftinguifhes * two facred Volumes, the one written, called 'the.#?£/i?; the other, Nature, or the World ; God 4 having manifefted himfelf by two Lights : the one of 4 Revelation, and the other of Demonftration. Accordingly, 4 the Interpreters of the former are Divines ; of the latter,

4 the Mathematicians are to be confulted; and as to the c Objects of Faith, the Prophets ; the former, being no lefs ( Interpreters, or Apoftles, from God to Men, than the latter. ' And as the Mathematician would be judg'd to wander out ' of his Province, if he Ihould pretend to controvert, or
 * Mathematicians. As to Matters of Natural Knowledge,

1 fo it muft be granted, the Divines are no lefs out of 1 their Limits, when they venture to pronounce on a Point ' of Natural Knowledge, beyond the Reach of any not
 * fet afide any Article of Faith from Principles ot Geometry 5


 * verfed in Geometry and Opticks, merely from Holy Scrip-

D d * ' ture,

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