GEOHCJK (iABHIEI. STOKHS. 775 



This last fact is perhaps wdrth iii-.isliiiii- on at the piociit tiiiic, 

 when the sej)ai-ali()ii hctwcni pure niatlicinatics and physics has he- 

 come far widci' than is advantageous for cither. The physicist works 

 mainly in his laboratory, tlie inatheniat ician at his desk, neither 

 intrenching on the domain of liic other. Kven tiie ina<:-nilicent work 

 of Poincare, introchicini;- tlie rigorous and friiitfid methods of pui-e 

 mathematics for the treatnuMit of physical j)rol)Ienis, is only a i)artial 

 step in the right direction. With Stokes this divorce never occurred; 

 expenment went hand in hand with theory. As early as 1840 he had 

 fitted up a small hd)oratory in his rooms, of sim])U' character it is true. 

 i)ut none the less suflicient to test, sometimes searchingly, the results 

 of his theories. And it was the same all through his life. He was 

 never content to leave a theory unconhrmed by experiment, aud if a 

 new observation were made it nnist be comi)ared with theory. These 

 qualities are especially noticeable in some of his earlier i)apers. In 

 that (m internal friction, he ex})lains the suspension of clouds aiul the 

 subsidence of ri])ples and waves after a stoi'ui: in those on oscillatory 

 wave motion, the well-known experiments of Scott Kussell are fully 

 considered; his ])aper on ditf'raction is divided into two parts, consist- 

 ing of his theory and of the experiments which he made to test it, and 

 so on. Later in life he would, in a short note or a few renuirks, <rive 

 the main outline of an explanation of some new phenomenon: fni-- 

 ther research by others usually proved him to be coi-rect. 



This active period quickly brought recognitiou to him. In 1S4!) he 

 succeeded to the Lucasian chair of uuithematics in Cambridge, a post 

 held previously by Isaac Barrow, Xewton. Woodhouse, Airy, and 

 Babbage, and five years later he was elected secretary to the Royal 

 Society. He was not content with delivering the two courses of 

 lectures required of the professor by the regulations. lie let it be 

 known that he considered it pai't of his duty to help students in their 

 work, and such helj) from a man like Stokes was not to be despised. 

 He was always ready to give a.ssistance, whether it was asked for 

 work already started, or in suggesting new problems to be under- 

 taken, or in giving encoui'agement wheiv failure seeuu'd likely. This 

 trait was even more conspicuous during his thirty-ou(> years' tenure 

 of the Royal Society position. Xaturally brought into contact with 

 all the best work which was f)eing done throughout the country, he 

 largely gave himself up to hel[)ing others. This was undoubtedly 

 the main reason for the smaller output after this time. As against 

 50 papers produced up to 185'2, we find only •")(') from then until the 

 end of 18S;5, and many of the latter consist of addresses and short 

 notes on such ssibjects as chemistry, details of insti-uments. and his- 

 tory of science, all valuable but ixn'haps not epoch-madving like the 

 earlier menu)irs. His reward was the frequent acknowledgment of 

 his assistance which those alone who had received knew how to appre- 



