Page:Cyclopaedia, Chambers - Volume 2.djvu/596

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In every thing elie he perfevered a Papift. — So that the Refor- mation went on but lamely in his time. — Under his Son Edward VI. it went much further ; but was all undone again by his Suc- ccflbr Queen Mary, who re-eftabliihed the antientSuperftitions.

But the Executions of above 500 People, who were burnt for the Proteftant Faith in the five Years of her Reign, Jo alienated the People from Popery, that Queen Elizabeth, her Sifter, found it no hard Matter to carry the Reformation to its full Length; and to fettle it on the Foot whereon it now Hands among us. See Protestant, Calvinist, &c.

Right of Reformation, Jus Reformations, is a Rightwhich the Princes oi Germany claim to reform the Church in their re- ipective Territories ; as being inverted with the fpiritual as well as the temporal Power.

The Jus Reformations is annex'd to the Principality ; by this they have the Power of Confcience, the Difpolition of Ecclefi- aftical Revenues, &c. as they enjoy'd the fame at the Treaty of jMunfier in 1624.

REFRACTED Ray, or Ray of Refraction. SeeRAY and Refraction.

Refracted Dials, are fuch as fhew the Hour by means of feme refracting tranfparent Fluid. See Dial.

If a Pin or Stick be fet up, or any Point be affign'd in a con- cave Bowl or Dilh, lor the Centre of the Dial ; and a horizontal Dial be applied over the lame ; aligning the meridian Line on the Edges of the Bowl ; and marking out the reft of the Hour Lines alfo on the Edges of the Bowl : Then taking alvay the horizontal Dial, and elevating a String or Thread from the End of the faid Pin over the meridian Line, as much as is the Lati- tude or Elevation of the Pole of the Place. — Then, by bringing the Thread to call a Shadow on any Hour-Point formerly mark'd out en the Edges of the Bowl, by a Candle or the like ; that Shade in the Bowl is the true Hour-Line : And if the Bowl be full of Water, & c. when this is done ; it will never fhew the true Hour b/ the Shadow of the Top of the Pin, but when filled again with the fame Liquor.

P.EFR ACTION, in Mechanicks, the Deviation of amoving Body from its direct Courfe, by reafon oi the different Denfity of the Medium it moves in ; or a Fiexion and Change of Deter- mination, occafioned by a Body's falling obliquely out of one Medium into another of a different Denfity. See Medium.

Thus a Ball A, {Tab. Mechanicks, F/g. 52.) moving in the Air in the Line AB, and falling obliquely on the Surface of the Wa- ter CD, does not proceed ftraight to E, but deviates or is inflected to B.— Again, if the Ball moving in Water in the fame Line AB fhould fall obliquely on a Surface of Air CD,- it will not proceed ftraight to E, nor yet deflect to F, but to G.

Now the Defledion in each Cafe is call'd the Refratlion; and the two Cafes are diftinguifhed by means of the Perpendicular MI; rhat, BG being called Refratlion towards the Perpendicular, or to the Axis of RefraSion; and the other BF, Refratlion from the Perpendicular, ox from the Axis of Refratlion.

Thefe Refractions are fuppofed to arife hence, that the Ball ar- rivng at B, in the firft Cafe, finds more Refiftance from the Side O, i. e. from the Side of the Water, than from the Side P, or that of the Air ; and in the latter more Refiftance from the Side P, which is now the Side of the Water, than the Side O which is that of the Air.

In effed the great Law of Refratlion which holds in all Bodies, and all Mediums, is, That a Body palling obliquely out of a lefs into a more refuting Medium, is refracted from the Perpendicular; and in palling out of a more into a lefs refitting Medium, is re- fracted towards the Perpendicular.

Hence the Rays of Light falling oat of Air into Water are re- fracted towards the Perpendicular;; whereas a Ball thrown into the Water is refracted from it; by realbn Water, which relifts the Motion of Light lefs than Air, relifts that of the Ball more : Or, to fpeak more juftiy, by reafon Water, by its greater At- traction, accelerates the Motion of the Rays of Light more than Air does: For that this is the true Caufe of Refratlion, at le^tft in Light, fliall be lliewn under Refraction of Light.

To have a Body refraBed, 'tis neceffary it fall obliquely on the fecond Medium. — In perpendicular Incidences there is no Re- fratlion.

Vojfius, indeed, and Snellius imagined they had obferved a per- pendicular Ray of Light undergo a Refratlion ; a perpendicular Object appearing in the Water nearer than in reality it was : But this was to attribute that to a Refraction of the perpendicular Rays, which was owing to the divergency of the oblique Rays after Re- fratlion, from a nearer Point.

Yet is there a manifeft Refratlion even of perpendicular Rays found in If and Cryftal. See Ifland Crystal.

Rohault adds, that though an oblique Incidence be neceffary in ah other Mediums we know of; yet the Obliquity mult not " c ^ ea a certain Degree.— If it do, the Body will not penetrate the Medi urrl; but be rcj??cfe/, inftead of refraBed.— Thus Cannon

f h\\7 CS ^ n Pg cmenrs ' falling very obliquely on the Surface o the \\ 3terj are orj f ervec i to mount; a _l ft again, and frequent- ly to iweep the Men from off' the oppofite Decks : And the like happens to the little Stones wherewith Children make their Ducks and Drakes.

The Antients confounded RefraSion with Reflexion; and 'twas

Sir Ifaac Newton, who firft taught us the Difference between them.— He ihews withall, that there is a good deal of Analogy be tween them; and particularly in the Cafe of Light. See Re- flection and Refraction of Light.

The Laws of Refratlion of the Rays of Light in Mediums differently terminated, i. e. whofe Surfaces are Plain, Concave, Convex, &c. make the Subject of Dioptricks. See Diop-

TRICKS.

By Refratlion it is that Convex Glades, or Lens's colled the Rays, magnify Objects, Burn, 6-c. and that concave Lens's dif- perfe the Rays, diminifh Objeds, <S-c. See Lens's, Convex, and Concave.

Hence the Foundation of Microfcopes, Telefcopes, &c. See Microscope and Telescope, &c.

By Refratlion it is, that all remote Objects are feen out of their real Places; particularly, that the heavenly Bodies arc ap- parently higher than they are in reality, ire. See Apparent and Place. See alfo Refraction Agronomical.

Refraction of Light, in Opticks, is an inflexion or deviati- on of the Rays from their rectilinear Courfe upon falling obliquely out of one Medium into another, of a different Denfity. SeeRAY.

The Refratlion of Light Sir Ifaac Newton ihews is not per- form'd by the Rays falling on the very Surface of Bodies ; buc without any Cositatl, by the Action of fome Power of the Bo- dies equally diffufed throughout their Surfaces ; by which fame Power acting in other Circumftances, they are alfo emitted and reflected. See Light.

The fame Arguments whereby we have proved that Rcfectim is perform'd without immediate Contact, go a great way towards demonftrating the fame of Refratlion : To which may be added rhe following ones.

1°. Becaufe if when Light falls out of Glafs into Air, with the utmoft Obliquity it will be tranfmitted at, it be then made to fall a little more obliquely, it becomes wholly reflected.— For, the Power of the Glafs after it have refracted Light emerging as ob- liquely as poffible, fuppofing the Rays to fall itill more obliquely, will be too llrong to let any of the Rays pafs; confequently, in- ftead of being refracled they will be all reflected.

2 . Becaufe in thin Lamella:, or Plates of Glafs, Light is re- flected and refraBed fcveral times alternately, as the tbicknefs of

the Lamella: increafes in arithmetical Progreffion For here it

depends on the thicknefs of the Lamina which of the two it fliall do; whether relied it, or let it be tranfmitted.

3°. Becaufe whereas the Powers of other Bodies both to reflect and refract Light are very nearly Proportional to their Denfities ; yet unctuous and fulphurous Bodies are found to reflect more ftrongly than according to their Denfities.— For as the Rays act more ftrongly on thofe Bodies to kindle them, than on others ,- fo do they, again, by their mutual Attradion, ad more ftrongly on the Rays to refratl them.

Laftly, Becaufe not only thofe Rays tranfmitted through Glafs are found to be refracled, but alio thofe Daffing in the Air, or in a Vacuum near its Extremities, or even near the Extremes of many Opake Bodies, e. gr. the Edge of a Knife, undergo a (imilar In- flexion, from the Attraction of the Body. See Inflection.

The manner wherein Refratlion is perform'd by meer Attracti- on, without Contact, may be thus accounted for Suppofe HI

(lab. Opticks, Fig. 56.) the Boundary of two Mediums, N and O • the firft the Rarer, e.gr.Aii; the fecond the Denier, e. gr. Glafs - the Attradion of the Medium here will be as their Denfities ~ Suppofe PS to be the Diltance to which the attracting Force of the denfer Medium exerts icfelf within the Rarer.

Let now a Ray of Light Ka fall obliquely on the Surface which feparates the Mediums; or rather, on the Surface PS, where the Action of the fecond and more refilling Medium com* mences. All Attraction being perform'd in Lines perpendicular to the attractive Body, as the Ray arrives at a, it will begin to be turned out of its rectilinear Courfe, by afuperiorForce where- with it is attracted by the Medium O, more tljan by the Medium N, i. e. by a Force wherewith it is dr.ven towards it in a Diredion perpendicular to its Surface.— Hence the Ray is bent out of its right Line, in every Point of its Paffage between PS and RT, within which the Attraction ads. Between thole Lines, there- fore it^ defcribes a Curve aSb. But beyond RT, beino- out of the Sphere of Attradion of the Medium N, it will proceed uni- formly in a right Line, according to the Diredion of the Curve in the Point b.

Again, fuppofe N the denfer and more refifting Medium, O the Rarer; and HI the Boundary, as before; and let RT be the Diltance to which the denfer Medium exerts its attradive Force within the Rarer : Even when the Ray has pafs'd the Point B, it will be within the Sphere of fuperior Attradion of the denfer Medium; but that Attraction ading in Lines perpendicular to its Surface, the Ray will be continually draw n from its ftraight Courfe BM perpendicularly towards HI: Thus having two forces or Di- redions, it will have a compound Motion, whereby inftead of BM it will deicribe Bra, which B?n, will in ltridnefs be a Curve.

Laftly, After it has anfved in w, beine out of the Influence of the Medium N, it will perlift uniformly in a right Line, in the Diredion wherein the Extreme of the Curve leaves it.

Thus we fee how Refratlion is performed, both toward the Perpendicular, and from it.

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