WEST OF ENGLAND JOURNAL 



OF 



No. HI. JULY, 1835. Vol. 1. 



PART I.— SCIENCE. 



REFLECTION AND REFRACTION OF LIGHT, 



y4s explained by Newton, Huygens, and a new Theory, in order to form a 



Comparison. 



BY THOMAS EXLEY, A. M. 



1. The phaenomena of light have always excited curious attention j but 

 optics as a science must have been exceedingly imperfect, before the law 

 of refraction was discovered by Snellius, early in the seventeenth century. 

 And, notwithstanding the recent very brilliant atchievements in this admir- 

 able science, refraction and reflection still remain the fundamental properties, 

 which present the true principle and grand instrument, in explaining all 

 known optical facts. These constitute the only key capable of opening 

 the radiant palaces of liglit. If these be explained satisfactorily, every 

 difficulty will vanish, and we shall proceed in broad day-light, clieerfully 

 enjoying the splendour of our subject. 



2. Tiie first philosophical explanation of the important law of refraction, 

 worthy of notice, is due to Huygens, who deduced his conclusions from 

 the theory of undulations, sui)pose(i to be propagated in spherical waves, 

 throiigii an universal and highly elastic medium or ether. 



To this succeeded Newton's elegant explanation, founded on specific 

 attractions and repulsions, operating at alternate distances between the 

 atoms of ligiit and those of contiguous bodies. 



3. Both the explanations are exceedingly ingenious, but both are con- 

 fessedly defective, for this reason, among others, that they rest on liypo- 

 thetica! principles, which have not been, and certainly never can be verified. 

 The unduiatory theory lias of late found many admirers, and able sup- 

 ])orter8. Indeed tlie facility witii wiiich it can, under due modifications, be 

 applied to (he solution of many intricate phaenomena, relating to diflfraetioa 

 and tlie jjolarisation of light, has given it an ascendancy over the New- 

 tonian theory. The general opinion seems to be, that one or other of these 

 must be true. Tliey are called the rival theories. I have ventured, how- 

 ever, in a Treatise on Physical Optics, lately published, to present cx- 



No. 3,— Vol. I. u 



