452 HISTORY OF OPTICS. 



related in these papers appears to us to be by far 

 the most important and interesting which has been 

 made in France concerning the properties of light, 

 at least since the time of Huyghens ; and it is so 

 much the more deserving of notice, as it greatly 

 influences the general balance of evidence in the 

 comparison of the undulatory and projectile theo- 

 ries of the nature of light." He then proceeds to 

 point out the main features in this comparison, 

 claiming justly a great advantage for the theory of 

 undulations on the two points we have been consi- 

 dering, the phenomena of diffraction and of double 

 refraction. And he adds, with reference to the em- 

 barrassment introduced by polarization, that we are 

 not to expect the course of scientific discovery to 

 run smooth and uninterrupted ; but that we are to 

 lay our account with partial obscurity and seeming 

 contradiction, which we may hope that time and 

 enlarged research will dissipate. And thus he 

 steadfastly held, with no blind prejudice, but with 

 unshaken confidence, his great philosophical trust, 

 the fortunes of the undulatory theory. It is here, 

 after the difficulties of polarization had come into 

 view, and before their solution had been discovered, 

 that we may place the darkest time of the history 

 of the theory ; and at this period Young was alone 

 in the field. 



It does not appear that the light dawned upon 

 him for some years. In the mean time, Young 

 found that his theory would explain dipolarized 



