THE UNDULATORY THEORY. 499 



many of this younger race of undulationists. For 

 besides MM. Cauchy, Poisson, and Ampere, M. Lame' 

 has been more recently following these researches in 

 France 25 . In Belgium, M. Quetelet has given great 

 attention to them; and, in our own country, Sir 

 William Hamilton, and Professor Lloyd, of Dublin, 

 have been followed by Mr. MacCullagh. Professor 

 Powell, of Oxford, has continued his researches 

 with unremitting industry; and, at Cambridge, 

 Professor Airy, who did much for the establish- 

 ment and diffusion of the theory before he was 

 removed to the post of Astronomer Royal, at Green- 

 wich, has had the satisfaction to see his labours con- 

 tinued by others, even to the most recent time; for 

 Mr. Kelland 26 , whom we have already mentioned, 

 and Mr. Archibald Smith 27 , the two persons who, in 

 1834 and 1836, received the highest mathematical 

 honours which that university can bestow, have 

 both of them published investigations respecting 

 the undulatory 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 



2S Prof. Lloyd's Report, p. 392. 



20 On the Dispersion of Light, as explained by the Hypothesis 

 of Finite Intervals. Camb. Trans, vol. vi. p. 153. 



27 Investigation of the Equation to Fresnel's Wave Surface, 

 ib. p. 85. See also, in the same volume, Mathematical Consi- 

 derations on the Problem of the Rainbow, showing it to belong 

 to Physical Optics, by R. Potter, Esq., of Queens' College. 



KK2 



