258 DISCOURSE ON THE STUDY 



Dr. Wollaston, who re-examined and verified the 

 laws of double refraction in Iceland spar announced 

 by Huyghens. Attention being thus drawn to the 

 subject, the geometry of Laplace soon found a means 

 of explaining at least one portion of the mystery 

 of this singular phenomenon, by the Newtonian 

 theory of light, applied under certain supposed con- 

 ditions ; and the reasoning which led him to the re- 

 sult (at that time quite unexpected), may justly be 

 regarded as one of his happiest efforts. The pro- 

 secution of the subject, which had now acquired a 

 high degree of interest, was encouraged by the offer 

 of a prize on the part of the French Academy of 

 Sciences ; and it was in a memoir which received this 

 honourable reward on that occasion, in 1810, that 

 Malus, a retired officer of engineers in the French 

 army, announced the great discovery of the polariza- 

 tion of light by ordinary reflection at the surface of 

 a transparent body. 



(286.) Malus found that when a beam of light is 

 reflected from the surface of such a body at a certain 

 angle, it acquires precisely the same singular pro- 

 perty which is impressed upon it in the act of double 

 refraction, and which Newton had before expressed 

 by saying that it possessed sides. This was the first 

 circumstance which pointed out a connection be- 

 tween that hitherto mysterious phenomenon and 

 any of the ordinary modifications of light ; and it 

 proved ultimately the means of bringing the whole 

 within the limits, if not of a complete explanation, 

 at least of a highly plausible theoretical represent- 

 ation. So true is, in science, the remark of Bacon, 



