THE NEW AVORLD-PICTURE OF MODERN 

 PHYSICS ' 



By SiK James H. Jeans 



The British Association assembles for the third time in Aberdeen — 

 under the happiest of auspices. It is good that we are meeting in 

 Scotland, for the Association has a tradition that its Scottish meet- 

 ings are wholly successful. It is good that we are meeting in the 

 sympathetic atmosphere of a university city, surrounded not only 

 by beautiful and venerable buildings, but also by buildings in which 

 scientific knowledge is being industriously and successfully accumu- 

 lated. And it is especially good that Aberdeen is rich not only in 

 scientific buildings but also in scientific associations. Most of us 

 can think of some master mind in his own subject who worked here. 

 My own thoughts, I need hardly say, turn to James Clerk Maxwell. 



Whatever our subject, there is one man who will be in our thoughts 

 in a very special sense tonight — Sir William Hardy, whom we had 

 hoped to see in the presidential chair this year. It was not to be, 

 and his early death, while still in the fullness of his powers, casts a 

 shadow in the minds of all of us. We all know of his distinguished 

 work in pure science, and his equally valuable achievements in 

 applied science. I will not try to pay tribute to these, since it has 

 been arranged that others, better qualified than myself, shall do so 

 in a special memorial lecture. Perhaps, however, I may be per- 

 mitted to bear testimony to the personal qualities of one whom I 

 was proud to call a friend for a large part of my life, and a colleague 

 for many years. Inside the council room his proposals were always 

 acute, often highly original, and invariably worthy of careful con- 

 sideration; outside, his big personality and wide range of interests 

 made him the most charming and versatile of friends. 



And now I must turn to the subject on which I have specially 

 undertaken to speak — the new world-picture presented to us by 

 modern physics. It is a full half century since this chair was last 

 occupied by a theoretical physicist in the person of the late Lord 

 Rayleigh. In that interval the main edifice of science has grown 



' Presidential address before the British Association for the Advancement of Science, 

 Aberdeen, 1934. Reprinted by permission from Nature, Sept. 8, 1934. 



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