REPORT ON OPTICS. 
313 
of hybernation all the genius and talent of France. Men of 
high endowments and lofty intellect found an elevated place in 
society ; and the establishment of the National Institute, the 
mightiest organization of intellectual power that history records, 
gave a new and a vigorous tone to scientific research. Even 
amid the convulsions and atrocities of that awful period, Science 
shot forth some of her brightest radiations ; and in the moral 
and religious darkness which prevailed, her evening star was 
the only surviving emblem of heaven. The impulse thus given 
to knowledge was propagated over all Europe ; and the quarter 
of a century which succeeded was one of the brightest periods 
in the history of philosophy. 
Although Sir Isaac Newton had determined the law of the 
colours of thin plates, and had begun to examine the pheno¬ 
mena of inflexion, yet his experiments on both these subjects, but 
especially the last, were left imperfect. The young and ardent 
minds that were now ambitious of following Newton in his career 
of discovery, chose the inflexion of light as the subject of their 
first achievements. Lord Chancellor Brougham, Dr. Young, 
and Mr. Jordan gave an account of their respective labours on 
this subject in elaborate and valuable Memoirs. Lord Brougham 
and Mr. Jordan were warm admirers of the Newtonian theory 
of light, but Dr. Young had adopted the undulatory hypothesis 
of Huygens ; he was therefore led to examine the phenomena 
under a different aspect, and was conducted to an experimental 
demonstration of the general law of interference, which was 
first observed by Grimaldi, and had been subsequently applied 
by Dr. Hooke to the explanation of the colours of thin plates. 
About the same time Ritter had discovered the deoxidating 
rays of the spectrum; Sir William Herschel had observed the 
invisible rays of heat; and Dr.Wollaston had detected fixed 
lines in the spectrum, and had confirmed by new experiments 
the Huygenian law of double refraction. During the same period 
the Marquis Laplace, who was a keen supporter of the New¬ 
tonian hypothesis, had referred the deviation of the extraordi¬ 
nary ray in doubly-refracting crystals to those attractive and re¬ 
pulsive forces by which the ordinary refraction and reflexion of 
light are performed ; and by considering the force which acts 
upon the extraordinary ray as a function of the angle which the 
refracted ray forms with the axis of the crystal, he obtained 
formulae perfectly coincident with the Huygenian law. 
The attention of philosophers was now anxiously directed to 
the subject of double refraction, and in 1808 the Institute of 
France proposed it as the subject of their Physical Prize. Thi&. 
prize was adjudged in 1810 to M. Mains, Colonel of the Imperial 
