ELECTRICAL STBUCTTJEE OF MATTER RUTHERFORD 183 



endeavored to outline some of the main arguments which should be 

 taken into account. 



I must now bring to an end my survey — I am afraid all too brief 

 and inadequate — of this great period of advance in physical science. 

 In the short time at my disposal it has been impossible for me, even 

 if I had the knowledge, to refer to the great advances made during 

 the period under consideration in all branches of pure and applied 

 science. I am well aware that in some departments the progress 

 made may justly compare with that of my own subject. In these 

 great additions to our knowledge of the structure of matter every 

 civilized nation has taken an active part, but we may be justly proud 

 that this country has made many fundamental contributions. With 

 this country I must properly include our dominions overseas, for 

 they have not been behindhand in their contributions to this new 

 knowledge. It is, I am sure, a matter of pride to this countr}'' that 

 the scientific men of our dominions have been responsible for some 

 of the most fundamental discoveries of this epoch, particularly in 

 radioactivity. 



This tide of advance was continuous from 1896, but there was an 

 inevitable slackening during the war. It is a matter of good omen 

 that in the last fcAv years the old rate of progress has not only been 

 maintained but even intensified,. and there appears to be no obvious 

 sign that this period of great advances has come to an end. There 

 has never been a time when the entliusiasm of the scientific workers 

 was greater, or when there was a more hopeful feeling that great 

 advances were imminent. This feeling is no doubt in part due to 

 the great improvement during this epoch of the technical methods 

 of attack, for problems that at one time seemed unattackable arc 

 now seen to be likely to fall before the new methods. In the main 

 the epoch under consideration has been an age of experiment, where 

 the experimenter has been the pioneer in the attack on new prob- 

 lems. At the same time it has been also an age of bold ideas in 

 theory, as the quantum theory and the theory of relativity so well 

 illustrate. 



I feel it is a great privilege to have witnessed this period, which 

 may almost be termed the renaissance of pliysics. It has been of 

 extraordinary intellectual interest to watch the gradual unfolding of 

 new ideas and the ever-changing methods of attack on difficult prob- 

 lems. It has been of great interest, too, to note the comparative sim- 

 plicity of the ideas that have ultimately emerged. For example, no 

 one could have anticipated that the general relation between the ele- 

 ments would prove to be of so simple a character as we now believe 

 it to be. It is an illustration of the fact that nature appears to work 

 in a simple way, and that the more fundamental the problem often 



