THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[SIXTH SERIES.] 



FEBRUARY 1919. 





XVII. The Ah sorption of X-R&ys^ 

 By Tycho E:SON Aurkn, Dr. phil* 



I. Method of Investigation. 



SINCE Moseley has ascertained that there is a simple 

 relation between the frequency of X-ray spectra 

 and atomic number, we may rendily assume that there 

 will be a similar relation when examining X-ray 

 absorption in different elements. By way of ascertaining 

 this kind of relation, I have made determinations of 

 absorption in a number of elements. In so doing I have 

 introduced a method of investigation which I have more 

 particularly described in a preliminary paper f . This 

 method has in view, by means of a procedure of com- 

 pensation and by using a non-homogeneous radiation, 

 the endeavour to determine the relation between the 

 absorption coefficient of a certain element and the same 

 coefficient of water. As materials for investigation I have 

 preferably made use of chemical solutions, because a great 

 number of elements are not obtainable in solid form, 

 whereas they are easily obtainable in soluble compounds. 

 As the method is adapted for determination of relative 

 absorption coefficients, and these, only excepting the 

 lightest elements, at least within a not too wide range, 



* Communicated by the Author. 

 t Phil. Mag. xxxiii. p. 471 (1917). 



Phil. Mag. S. 6. Vol. 37. No. 218. Feb. 1919. N 



