G. G. Stokes, J. C. Adams 125 



right, of course, with regard to all phenomena known to 

 him, and the proposition that the refrangibility of a ray of 

 light cannot be altered by reflexion or refraction was a 

 great step in advance at the time. As constantly happens, 

 however, new facts require a revision of old dogmas, and 

 though Brewster could never be persuaded, Stokes showed 

 in an absolutely conclusive manner that certain substances 

 could, and did, alter the refrangibility, or, as we now should 

 say, absorbed the incident light and emitted it again with 

 different periods of oscillation. As fluor spar was one of the 

 substances possessing this peculiar property, Stokes called 

 the whole series of phenomena " fluorescence." 



The later years of Stokes' life centred largely in his 

 activity as Secretary of the Royal Society. The range of 

 his knowledge, the width of his sympathies, and his almost 

 infallible judgment, peculiarly fitted him for a position which 

 offered so many opportunities of advising striving men, and 

 guiding their researches into profitable directions. He died 

 an old man, but his scientific outlook always remained young. 

 New ideas pleased him, even when he could not agree with 

 them, and he delighted in any discovery that did not fit into 

 established theories. 



Two years after Stokes graduated as senior wrangler and 

 first Smith's prize man, the same honours fell to John Crouch 

 Adams (1819-1892). There could be no sharper contrast 

 between two men of similar intellectual attainments than that 

 which marks the scientific life of the two mathematicians. 

 Stokes freely presented his knowledge and experience to 

 others, while to Adams we may apply with greater truth 

 what Maxwell said of Cavendish, that he cared more for 

 doing the work than for communicating it to others. How 

 much of this reserve was due to the events connected with 

 his first research it is impossible to say, but it is difficult 

 to believe that these left him entirely unaffected. For that 

 research was an arduous one, and should have led to the first 

 discovery of the planet Neptune, if the responsible astro- 

 nomers at the time had paid more attention to the calculations 

 of the young Cambridge mathematician. A full account of 

 the history of the new planet, from the pen of Simon 

 Newcomb, is published in the " Encyclopaedia Britannica," 



