GEORGE GABRIEL STOKES. 7 i 5 



This last fact is perhaps worth insisting on at the present time, 

 when the separation between pure mathematics and physics lias be- 

 come far wider than is advantageous for either. The physicist works 

 mainly in his lal)()ratory, the mathematician at his desk, neither 

 intrenching on the domain of the other. Even th(> magnificent work 

 of Poincare, introducing the rigorous and fruitful nu'thods of pure 

 mathematics foi- the treatment of j)hysical problems, is only a partial 

 step in the right direction. ^\\{\\ Stokes this divorce never occurred; 

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

 fitted up a small laboratory in his rooms, of simple character it is true, 

 ijut none the less sufficient to test, sometimes searcliingly, the results 

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

 never content to leave a theoiy unconiirnuHl by experiment, and if a 

 new observation were made it must be compared Avitli theory. These 

 qualities are esjxK'ially noticeable in some of Ids earlier j)ai)ers. In 

 that on internal fi'iction, he exi)lains the suspension of clouds and the 

 subsidence of rij)ples aiul waves after a storm; in those on oscillatory 

 wave motion, the welbknown experiments of Scott Hussell are Piilly 

 considered; his })aper on dilfraction is divided into two parts, consist- 

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

 so on. Later in life he would, in a short note or a few remarks, aive 

 the main outline of an explanation of some new phenomenon; fur- 

 ther research by others usually proved him to be correct. 



This active period quickly brought recognition to him. In 184!) he 

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

 held previously by Isaac Barrow, New'ton. 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. He let it be 

 known that he considered it ])art of his duty to help students in their 

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

 He was always ready to give assistance, whether it was asked for 

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

 taken, or in giving encouragement where failure seemed likely. This 

 trait was even more conspicuous during his thirty-one years' tenure 

 of the Royal Society position. Naturally brought into contact with 

 all the best worlv which was being done throughout the country, he 

 largely gave himself u]) to helping others. This was undoul)tedly 

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

 50 ])apers produced up to ISH-J. we find only .Mi from then until the 

 end of 1888, and many of the latter consist of addresses and short 

 notes on such subjects as chemistry, details of instruments, and his- 

 tory of science, all \aluable but ])erha])> not epocli-making like the 

 earlier memoii-s. His i-eward was the frequent aclviiowledgment of 

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



