Quantum-theory and Rotation-Energy of Molecules. 71 



by the treasures of infinitely manifold mental work transmitted to 

 you by your teachers. But do not believe that all that is offered 

 to you from the Chair is the last word in wisdom. So long as 

 there is progress in Science, so long it will be subject to temporary 

 error. He who has got so far that he never errs, has ceased to 

 work. If, therefore, doubts and difficulties occur to you in your 

 studies, do not consider them something unpleasant or forbidden 

 which must be shaken off or suppressed, but seek out their 

 meaning carefully, and go to your Teachers (who are your guides), 

 trust in their riper experience, and cling to the hope of attaining 

 a gradually increasing understanding of dark and difficult 

 questions by means of conscientious and sustained effort ; and 

 so secure the fullest and truest scientific advancement. 



And if your honest efforts, verified by many tests, decisively 

 indicate to you new paths differing from the old, then — follow 

 your own conviction be} r ond any other. That is and must remain 

 your highest, your most precious possession; for just as training 

 for scientific independence is the highest aim of academic in- 

 struction, so does a scientific conviction acquired by honest work 

 give a firm anchorage for holding fast to a moral conception of the 

 universe in face of all the vicissitudes of life. 



The noblest among all the moral fruits of science, and that 

 which is peculiarly its own, is Truthfulness : that truthfulness 

 which leads through the sense of personal responsibility to inner 

 Freedom, and whose estimation in our present public and private 

 life should be much higher than it is. In whatever degree our 

 younger generation takes part in the fight to win for Truth an ever 

 fuller recognition, to that extent it may feel at one with those 

 heroes who, a hundred years ago, sealed the genuineness of their 

 love for the Fatherland with their hearts' blood. With such 

 memories and such thoughts, let us enter upon the work of the 

 new Session. 



X. On the Quantum-theory and the Rotation- Energy of 

 Molecules. By Eva von Bahr, Dr. phil. Uppsala*.' 



HPHE application of the quantum-theory to phenomena 

 JL connected with the rotation-energy of molecules 

 appears still more difficult to justify than in the case of the 

 vibration-energy of molecules or electrons. In the latter case 

 we have a fixed frequency, but this cannot be assumed for a 

 freely rotating molecule, which we have at least been ac- 

 customed to look upon as continuously varying in its rotation- 

 velocity, as well as in its translation-velocity. 



However, as early as 1911 Nernst f points out that, in 

 dealing with molecular rotation, we must probably introduce 



* Communicated bv the Author. 



t W. Nernst, Zeitschr. f. Elektroch. xvii. p. 265 (1911). 



