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LXVIL On the Einstein Spectral Line Effect. By H. J.. 

 Priestley, Professor of Mathematics, University of 

 Queensland*. 



r |^HE prediction of the Einstein displacement of the 

 A. spectral lines is based on two assumptions, namely : 



(a) the atom behaves as a natural clock, giving a value 



o£ ds which is the same for each vibration ; 



(b) the time period dt of a vibration is transmitted by 



the radiation from the source to the observer. 



If we assume, as an alternative to (6), that the Einstein 

 interval ds is transmitted by the radiation, the effect will 

 arise on the transference, not of the source, but of the 

 observer to a different gravitational field. The object of 

 the present paper is to discuss the reasonableness of rejecting 

 (b) and adopting the alternative. 



The usual method of discussing the deflexion of a beam of 

 light by a gravitating field, by applying the principle of Least 

 Time to determine the course of a ray propagated in three- 

 dimensional space with velocity l — 2mr~ 1 , leads one towards 

 the adoption of (h). The use of the principle of Least Time 

 appears to imply an underlying constancy of period. Conse- 

 quently it is advisable to investigate the deflexion by a 

 method which makes no appeal to Pre-Relativity Physics. 



The equations obtained from 



0, 



SjA 



ds 2 = -- 7 - l dr 2 - r 2 dcj> 2 + ydt 2 , 



are 



/dr\* ,/^V 79 ., 2m n h 2 



4H> •'■'■'■ w 



where h and k are constant. 



Elimination of s from (1) and (2) by means of (3) 

 leads to 



. 4!=^- ^ 



* Communicated by tie Author. 



