130 HISTORY OF OPTICS. 



Belgium, M. Quctelct has given great attention to them ; and, in our 

 own country, Sir "William Hamilton, and Professor Lloyd, of Dublin, 

 have been followed by Mr. Mac Cullagh. Professor Powell, of Oxford, 

 has continued his researches with unremitting industry ; and, at Cam 

 bridge, Professor Airy, who did much for the establishment and diffu- 

 sion of the theory before he was removed to the post of Astronomer 

 Royal, at Greenwich, has had the satisfaction to see his labors continued 

 by others, even to the most recent time ; for Mr. Kelland, 85 Avhom we 

 have already mentioned, and Mr. Archibald Smith," the two persons 

 who, in 1834 and 1836, received the highest mathematical honors 

 which that university can bestow, have both of them published inves- 

 tigations respecting the nndulatory theory. 



We may be permitted to add, as a reflection obviously suggested by 

 these facts, that the cause of the progress of science is incalculably 

 benefited by the existence of a body of men, trained and stimulated 

 to the study of the higher mathematics, such as exist in the British 

 universities, who are thus prepared, when an abstruse and sublime 

 theory comes before the world with all the characters of truth, to 

 appreciate its evidence, to take steady hold of its principles, to pursue 

 its calculations, and thus to convert into a portion of the permanent 

 treasure and inheritance of the civilized world, discoveries which might 

 otherwise expire with the great geniuses who produced them, and be 

 lost for ages, as, in former times, great scientific discoveries have some- 

 times been. 



The reader who is acquainted with the history of recent optical dis- 

 covery, will see that we have omitted much which has justly excited 

 admiration ; as, for example, the phenomena produced by glass under 

 heat or pressure, noticed by MM. Lobeck, and Biot, and Brewstcr, and 

 many most curious properties of particular minerals. We have omit- 

 ted, too, all notice of the phenomena and laws of the absorption of 

 light, which hitherto stand unconnected with the theory. But in this 

 we have not materially deviated from our main design ; for our end, 

 in what we have done, has been to trace the advances of Optics 



20 On the Dispersion of Light, as explained by the Hypothesis of Finite Inter- 

 vals. Camb. Trans, vol. vi. p. 153. 



57 Investiyation of the Equation to FremePs Wave Surface, ib. p. 85. See 

 also, in the same volume, Mathematical Considerations on the Problem of the 

 Rainbow, showing it to belong to Physical Optics, by R. Potter, Esq , of Queen's 

 College. 



