THE UNITY OF SCIENCE 7 



of time surpasses in boldness anything which has hitherto 

 been achieved in scientific speculation or even in the philo- 

 sophical theory of knowledge ; in comparison with it the non- 

 Euclidian geometry is but child's play. And yet, in contrast 

 with the non-Euclidian geometry — which has thus far had 

 serious application only in the field of pure mathematics — the 

 relativity-principle justly claims a real physical significance. 

 With the revolution which it brings about in our conception of 

 the physical universe no other is comparable, in range and 

 profundity, except that due to the introduction of the Coper- 

 nican astronomy. "^ 



As for physics and chemistry, you may read in the cur- 

 rent number of one of our popular magazines how funda- 

 mentally they seem, in the eyes of a distinguished English 

 physicist, to have become new sciences within the present de- 

 cade. "Truly", observes Professor Soddy, "it may be said 

 that only in the present century have we become cognizant 

 of the major forces of the universe, which rejuvenate it 

 perenially and which guide and control its destiny and ours . . . 

 It sounds incredible, but nevertheless it is true, that science 

 up to the close of the nineteenth century had no suspicion 

 even of the existence of the original sources of natural 

 energy. . . .The vista which has been opened up by these new 

 discoveries (of the radio-active properties of some substances) 

 admittedly is without parallel in the whole history of 

 science."* 



Words equally ardent and hopeful, and expressive of an 

 equally keen sense of the novelty of the present situation in 

 tneir science, might be quoted, if time permitted, from some 

 of the leaders of contemporary biology. Though I may not 

 delay for further citations, I cannot forbear reminding you 

 how preeminent a place the opening years of the present de- 



3 Max Planck, "Acht Vorlesungen ueber theoretische Physik," p. 119. 

 The citation is added in revision ; for calling his attention to it the writer 

 is indebted to Professor C. M. Sparrow of the University of Virigina. 



4 Soddy in Harper's Magazine, December, 1909, p. 53. 



