of Physical Knowledge . 6 1 



Session in an Address concerning the beginning of the Course of 

 Studies, as the Statutes prescribe. 



Rather special are the feelings with which on this occasion we, 

 Teachers and Taught, regard the problems facing us in the new 

 Term ; for while the year just passed appears bathed in a festive 

 glory, illumined and warmed over its whole course by the thought 

 of national ideas, of the heavy sacrifices brought and of glorious 

 resulting victories, — the last and greatest of which is to be cele- 

 brated in these days by the whole German people, — the coming 

 Term appears, on the other hand, likely to bear an everyday 

 character and to be devoted to regular work. 



The best we can derive from the Memorial festivities of the 

 past year is the fervent wish that our successors may at some 

 future time look up to us as we look up to those men who, one 

 hundred years ago, fought and suffered in word and deed for the 

 Fatherland. Let no one reject such a wish as entirely baseless, 

 on the ground that such high aims cannot be contemplated to-day. 

 For, in the first place, we must not forget that the forces which 

 were then gloriously displayed derived their real strength from 

 the quiet everyday work of the simpler times preceding, which 

 may not have been so conscious of their high import but may have 

 been all the more intense and creative ; and in the second place, 

 none of us can know with what standard coming generations 

 may approach the estimate of our present-day performances. But 

 what we can assert with certainty, under all circumstances, is 

 that our generation can only hope to be judged honourably by 

 posterity if it endeavours to solve its own problems according to 

 its lights, in strict fulfilment of its duties : each one in the place 

 to which his calling and his fortune have led him. 



So then may I be allowed to-day to lav before you a section of 

 the special work going on within the Science I represent, by a 

 survey of the progressive development of Physical Knowledge and 

 an endeavour to sketch those new paths which it has trodden 

 since the beginning of this century. 



NEVER, probably, has experimental physical investi- 

 gation experienced so strenuous an advance as during 

 the last generation, and never probably has the perception of 

 it- significance for human culture penetrated into wider 

 circles than it does today. The Waves of Wireless Telegraphy, 

 Electrons, Rontgen Rays, the Phenomena of Radio-activity, 

 appeal more or less to the interesf of everyone. But if we 

 face the larger question in what respect have these new ami 

 brilliant discoveries influenced and advanced our under- 

 standing of Nature and her laws, the outlook, at first glance, 

 does not appear at all correspondingly brilliant. On the 

 contrary, whoever endeavours to judge of the state of 

 present Physical theories from a higher point of view, may 



