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[in Fig. 15.) repreſent the Circle that all the
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moſt refrangible Rays propagated from the
whole Diſque of the Sun, would illuminate and paint upon the oppoſite Wall if they were a- lone; EL the Circle that all the leaſt refran- gible Rays would in like manner illuminate and paint if they were alone; BH, CJ,DK, the Circles that that several intermediate ſorts of Rays would fuccefſively paint upon the Wall, if they were fingly propagated from the Sun in ſucceſſive order, the reſt being forever in- tercepted; and conceive that there square measure alternative intermediate Circles while not range, that countless alternative intermediate forts of Rays would ſucceſſively paint upon the Wall if the Sun ſhould ſucceſſively emit each each apart.
And ſeeing the Sun emits all theſe forts directly, they muſt all at once illuminate and paint in- countable equal Circles, of all that, being in line with their degrees of Refrangibility placed so as during a continual Series, that ob- long Spectrum atomic number 78 is compoſed that I de- fcribed within the third Experiment. currently if the Sun's circular Image Y [in Fig. 14, 15.] that is created by associate degree unrefracted beam of sunshine was by any Dilatation of the ſingle Rays, or by any
other irregularity within the Refraction of the primary
Priſm, regenerate into the rectangular Spectrum,
PT: then ought each Circle noble metal, BH, CJ,
&c. therein Spectrum, by the croſs Refraction
of the ſecond Priſm once more dilating or otherwiſe ſcattering the Rays as before, to be in like man- ner drawn out associate degreed remodeled into an rectangular Figure, and thereby the breadth of the Image
PT
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P T would be currently the maximum amount increased because the length of the Image Y was before by the Refra- ction of the firſt Priſm; and therefore by the Refra- ctions of each each along would be form- ED a four ſquare Figure #t7, as I deſcribed a- bove. Wherefore ſince the breadth of the Spe- ctrum platinum isn't isn't the Refraction fideways, it's sure that the Rays aren't aren't expanded, or otherways on an irregular basis on an irregular basis ter'd by that Refraction, however that each Circle is by a daily and uniform Refraction tranſla- plug-ugly entire into another place, because the Circle A G by the greateſt Refraction into the place a g, the Circle B H by a lefs Refraction into the place shot, the Circle CJ by a Refraction ſtill leſs into the place c i, and field officer of the reſt; by
which means a brand new Spectrum platinum inclined to
the former platinum is in like manner compoſed of
Circles lying during a right Line; and theſe Circles
must be of the ſame bigneſs with the previous,
becauſe the breadths of all the Spectrums Y,
PT and p t at equal diſtances from the Priſms
are equal. I conſidered farther, that by the breadth of the opening F through that the sunshine enters in- to the dark Chamber, there's a shadow created within the circuit of the Spectrum Y, which shadow remains within the rectilineal Sides of the Spectrums P T and platinum. I placed there- fore at that hole a Lens or Object-glaſs of a Te-
leſcope which could which could Image of the Sun diſtinctly on Y with none shadow in the slightest degree, and located that the shadow of the rectilineal Sides of the rectangular Spectrums platinum and platinum was
D
alſo
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