176 Intelligence and Miscellaneous Articles, 



elements makes them rather unsuitable as anticathodes in X-ray 

 tabes, and partly on account of the extreme absorbability of 

 the radiation from many of the elements. Nevertheless, by his 

 wonderful energy and by an ingeniously simple experimental 

 arrangement for photographing the X-ray spectra, Moseley in less 

 than half a year obtained measurements of the wave-lengths of the 

 most intense lines in the high-frequency spectra of the greater 

 part of the known elements and discovered the fundamental laws, 

 which will always bear his name*. This work, begun in Manchester, 

 was completed in Oxford in the early spring of 1914. As is well 

 known, Moseley found that the frequencies of the principal lines 

 in the high-frequency spectra are simple functions of the whole 

 number which represents the position of the elements in the 

 periodic table of Mendelejefr*. The extreme importance of this 

 result is that it reveals a relation between properties of different 

 elements far simpler than any which could be expected from pro- 

 perties previously investigated, all of which, including the ordinary- 

 visible spectra, vary in an intricate manner from element to 

 element. Moseley's discovery therefore gives a most important 

 clue to the question of the internal structure of the atom which 

 has received so much attention in recent years. "While it is hardly 

 the place here to enter into this problem in any detail, the general 

 importance of Moseley's results is perhaps best illustrated by the 

 fact that they enabled him to predict with certainty the number 

 of possible elements hitherto unknown and their position in the 

 periodic series. In this way he was, for instance, able to fix the 

 number of possible elements in the group of the rare earths ; and 

 just before he went to Australia he was occupied in collaboration 

 with Prof. Urbain on an investigation of the high-frequency 

 spectra of the elements of this group, which no doubt will 

 throw very much light upon this field of investigation which 

 hitherto has given chemists so much trouble. A full account of 

 this investigation has not yet been published, but Moseley gave a 

 paper on the general question before the Meeting of the British 

 Association in Sydney. 



Every reader of Moseley's papers will be strongly impressed 

 by his penetrating theoretical understanding and his great 

 experimental skill which, together with his unique capacity for 

 work, have secured him a place among the foremost workers in 

 science of his time, although he was not able to devote more 

 than four short years to scientific investigations. 



* Moseley, Phil. Mag. xxvi. p. 1024 (1913), and xxvii. p. 703 (1914). 



