14 Anniversary Address by Prof. C. S. Sherrington. 



such a relationship was yet productive of much valuable research on optical 

 isomerides in his own laboratory, and stimulated the efforts of many investi- 

 gators in that branch of physical chemistry, particularly in this country. 



Shortly after he had put forward his theory of the "product of asymmetry" 

 he was attracted by the problems connected with Van der Waal's equation 

 and the critical state, and, from his interest in these, two important lines 

 of investigation opened out. The one had relation to the degree of 

 molecular complexity of matter in the liquid state, and occupied his 

 attention mainly between the years 1893 and 1911. The other led him 

 at the beginning of the present century to advocate, with much energy and 

 persistence, the advantages of the physical method of determining atomic 

 weights. In this field of work he became one of the foremost investigators ; 

 his work on the calculation of precise gas densities was followed by chemical 

 studies of the atomic weights of nitrogen, silver and chlorine, and by 

 inquiries into sources of error, hitherto little recognised, in atomic weight 

 determinations. 



The Hughes Medal is awarded to Prof. Niels Bohr. 



Prof. Bohr is well known to all physicists as the author of the conception 

 to which the name " Bohr-atom " has been attached. A decade ago it became 

 clear, from the researches of Sir E. Eutherford and others, that the atom of 

 any element is formed out of an excessively minute positive nucleus of 

 electricity, round which circulate a number of negative electrons equal to the 

 atomic number of the element. Bohr discovered a mechanism for the 

 motion of these electrons, which solved immediately the long-standing puzzle 

 of the Balmer series of hydrogen, and which, after development and discus- 

 sion, appears likely to provide a complete explanation of the spectra of the 

 various elements. In this way he has opened up a line of investigation 

 which has already attracted to itself many of the ablest mathematicians in 

 Europe, and of which the success, in the simplest cases of the two light 

 elements hydrogen and helium, is even now little short of perfect. 



