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CHAPTER V. 

 DISCOVERIES ADDED TO THE NEWTONIAN THEORY. 



Sect. I. Tables of Astronomical Refraction. 



WE have travelled over an immense field of 

 astronomical and mathematical labour in the 

 last few pages, and have yet, at the end of every 

 step, still found ourselves under the jurisdiction of 

 the Newtonian laws. We are reminded of the uni- 

 versal monarchies, where a man could not escape 

 from the empire without quitting the world. We 

 have now to notice some other discoveries, in which 

 this reference to the law of universal gravitation 

 is less immediate and obvious; I mean the astro- 

 nomical discoveries respecting Light. 



The general truths to which the establishment 

 of the true laws of Atmospheric Refraction led 

 astronomers, were the law of Deflection, which ap- 

 plies to all refractions, and the real structure and 

 size of the Atmosphere, so far as it became known. 

 The great discoveries of Romer, and Bradley, 

 namely, the Velocity of Light, the Aberration of 

 Light, and the Nutation of the earth's axis, gave 

 a new distinctness to the conceptions of the pro- 

 pagation of light in the minds of philosophers, 

 and confirmed the doctrines of Copernicus, Kepler, 



