262 DISCOURSE ON THE STUDY 



(290.) Taking this as the groundwork of his 

 reasoning, Fresnel succeeded in erecting on it a 

 theory of polarization and double refraction, so 

 happy in its adaptation to facts, and in the coin- 

 cidence with experience of results deduced from it 

 by the most intricate analysis, that it is difficult to 

 conceive it unfounded. If it be so, it is at least the 

 most curiously artificial system that science has yet 

 witnessed ; and whether it be so or not, so long as 

 it serves to group together in one comprehensive 

 point of view a mass of facts almost infinite in 

 number and variety, to reason from one to another, 

 and to establish analogies and relations between 

 them ; on whatever hypothesis it may be founded, 

 or whatever arbitrary assumptions it may make 

 respecting structures and modes of action, it can 

 never be regarded as other than a most real and 

 important accession to our knowledge. 



(291.) Still, it is by no means impossible that the 

 Newtonian theory of light, if cultivated with equal 

 diligence with the Huyghenian, might lead to an 

 equally plausible explanation of phenomena now 

 regarded as beyond its reach. M. Biot is the au- 

 thor of the hypothesis we have already mentioned 

 of a rotatory motion of the particles of light about 

 their axes. He has employed it only for a very 

 limited purpose ; but it might doubtless be carried 

 much farther; and by admitting only the regular 

 emission of the luminous particles at equal intervals 

 of time, and in similar states of motion from the 

 shining body, which does not seem a very forced sup- 

 position, all tho phenomena of interference at least 



