MATHEMATICAL PHYSICS. 509 



ing that it will in due course engage the attention of the section, and 

 that we may look forward to interesting and stimulating discussions, 

 in which we trust the many distinguished foreign physicists who honor 

 us by their presence will take an active part. 



It is, I believe, not an unknown thing for your president to look 

 up the records of previous meetings in search of inspiration, and pos- 

 sibly of an example. I have myself not had to look very far, for I 

 found that when the British Association last met in Cambridge, in the 

 year 1862, this section was presided over by Stokes, and moreover that 

 the address which he gave was probably the shortest ever made on such 

 an occasion, for it occupies only half a page of the report, and took, I 

 should say, some three or four minutes to deliver. It would be to the 

 advantage of the business of the meeting, and to my own great relief, 

 if I had the courage to follow so attractive a precedent; but I fear that 

 the tradition which has since established itself is too strong for me to 

 break without presumption. I will turn, therefore, in the first in- 

 stance, to a theme which, I think, naturally presents itself — viz., a con- 

 sideration of the place occupied by Stokes in the development of mathe- 

 matical physics. It is not proposed to attempt an examination or ap- 

 preciation of his own individual achievements; this has lately been 

 done by more than one hand, and in the most authoritative manner. 

 But it is part of the greatness of the man that his work can be re- 

 viewed from more than one standpoint. What I specially wish to 

 direct attention to on this occasion is the historical or evolutionary rela- 

 tion in which he stands to predecessors and followers in the above field. 



The early years of Stokes's life were the closing years of a mighty 

 generation of mathematicians and mathematical physicists. When he 

 came to manhood, Lagrange, Laplace, Poisson, Fourier, Fresnel, Am- 

 pere had but recently passed away. Cauchy alone of this race of giants 

 was still alive and productive. It is upon these men that we must look 

 as the immediate intellectual ancestors of Stokes, for, although Gauss 

 and F. Neumann were alive and flourishing, the interaction of German 

 and English science was at that time not very great. It is noteworthy, 

 however, that the development of the modern German school of mathe- 

 matical physics, represented by Helmholtz and Kirchoff, in linear suc- 

 cession to Neumann, ran in many respects closely parallel to the work 

 of Stokes and his followers. 



When the foundations of analytical dynamics had been laid by Eu- 

 ler and d'Alembert, the first important application was naturally to 

 the problems of gravitational astronomy; this formed, of course, the 

 chief work of Laplace, Lagrange and others. Afterwards came the 

 theoretical study of elasticity, conduction of heat, statical electricity, 

 and magnetism. The investigations in elasticity were undertaken 

 mainly in relation to physical optics, with the hope of finding a mate- 



