OF ARTS AND SCIENCES: JUNE 9, 1868. 39 



Brewster's own prediction has the promise of fulfilment, — " I have no 

 doubt that, before another century is completed, a talking and a sing- 

 ing machine will be numbered among the conquests of science." 

 Born at a time when the corpuscular theory of light compelled assent, 

 from the influence of Newton's great name, when Laplace would nbt 

 tolerate any discussion of the opposing theory in the French Academy 

 of Science, when Lord Brougham fiercely attacked what he after- 

 wards cordially espoused, he lived to witness the complete triumph 

 of the undulatory theory in the hands of Young and Fresnel, and to 

 see what Lloyd has called " a mob of hypotheses " exchanged for what 

 Herschel characterizes as " one succession of felicities." Though 

 neither himself nor Biot ever deserted the lost cause, of which they 

 were the bold experimental champions, Brewster, in his Report on 

 Optics, prepared for the British Association for the Advancement of 

 Science, has done ample justice to the labors of Malus and others 

 who contributed to its overthrow ; and he congratulates mankind that 

 " 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." 



Of nearly one hundred papers which Brewster published in scien- 

 tific journals or in the transactions of academies, there are very few 

 which do not touch his favorite subject, viz., Optics. Optical instru- 

 ments ; polarization, rectilinear, circular, and elliptical ; depolarization ; 

 the optical character of crystals, and the mode of producing crystalline 

 structure artificially ; vision, both subjective and objective ; the action 

 of the eye in man and other animals ; the interference, dispersion, and 

 absorption of light ; the spectral lines in sunlight, as produced by the 

 sun's atmosphere, or the earth's atmosphere, and as multiplied by 

 other absorbing media; — this was the burden of his long life of 

 research and of his voluminous writings. 



Born seven years after Biot, Brewster died about seven years later, 

 so that the long and laborious lives of these two eminent physicists went 

 hand in hand for more than half a century. If Brewster did not 

 share the great mathematical powers of Biot, if he was without the 

 genius for vast and rapid generalization displayed by Fresnel in optics 

 and by Ampere in electro-magnetism, nevertheless he was endowed 

 with consummate skill in experiment, and deduced empirical laws 

 where Malus and Arago had failed. We may adopt the language 



