474 Anniversary Meeting. [Dec. 1, 



animals, lie was able to map out the most important motor areas with 

 great precision ; but, not content with the investigation of motor 

 centres, he experimented on the localisation of sensory centres in the 

 brain, and not only showed the existence of such centres, but deter- 

 mined their position. And if in the numerous observations which 

 have been subsequently made by other inquirers results somewhat 

 differing from his own have been obtained, the main outlines of 

 his conclusions have been confirmed. As so often happens, these 

 researches, purely scientific in the first instance, have been turned to 

 practical account. Dr. Ferrier himself predicted the application of 

 cerebral localisation to cerebral surgery. This application others have 

 already made, and his prediction is now being, fulfilled with brilliant 

 results. 



The other Royal Medal has been awarded to our Fellow, Dr. John 

 Hopkinson, for his researches in magnetism and electricity. 



Dr. Hopkinson's researches in magnetism comprise investigations 

 of the effect of temperature upon the magnetic properties of iron, 

 nickel, and various alloys of these metals (' Phil. Trans.,' 1889, A, 

 p. 443). It was known that for small magnetising forces the mag- 

 netisation of iron, nickel, and cobalt increases with increase of 

 temperature until we approach a certain temperature, which may be 

 called the critical temperature, on passing which the magnetism almost 

 suddenly disappears. Dr. Hopkinson's experiments show that for small 

 magnetising forces not only doe.s the magnetisation increase with ri^e 

 of temperature, but on approaching the critical temperature the 

 increase becomes extremely rapid, and then, on still further increase 

 of temperature, the magnetism suddenly almost entirely disappears. 

 He has further determined the critical temperature for various 

 samples of iron and steel. He has also measured the rapid change 

 which takes place in the temperatm*e coefficient of electrical resistance 

 in the neighbourhood of the critical temperature, and has shown that, 

 as had been conjectured, it is really at the critical temperature that 

 the phenomenon of recaleseence takes place. 



Dr. Hopkinson's contributions to the theory of dynamo-electric 

 machinery are most important. The method, now so extensively 

 used, of solving problems relating to dynamos by the use of what 

 M. Deprez has called the " characteristic curve," is due to him. 



He has also made a series of determinations of the specific induc- 

 tive capacities and refractive indices of a large number of transparent 

 dielectrics, the results of which are of great importance in the 

 theories of electricity and light. 



The Davy Medal has been awarded to Professor Emil Fischer for 

 his discoveries in organic chemistry, and especially for his researches 

 on the carbo-hydrates. 



To him, in conjunction with Otto Fischer, we owe the determina- 



