742 Dr. Tycho E:son Auren on Scattering and 



formula (7) and by the empirical formula 



0-00445- 



- = ( 



> ( v 



where X is expressed in Angstrom's units. 



Table V. 



Notation. 



A*. 



^0 



— calculated 



<7o 







observed. 



by form. 7; 



by form. 8. 



I 



0-359 



0-969 



0-925 



0-966 



II 



0-302 



0-953 



0896 



0-951 



Ill 



0-264 



0-935 



0-867 



0936 



IY 



0237 



0-920 



0-838 



0921 



Y 



0-215 



0-902 



0-807 



0-904 



YI 



0194 



0-879 



0-770 



0-882 



It will be seen from the table that the empirical formula 



(8) agrees very closely with the experimental values of — , 



whereas formula (7) gives values which decrease with 

 decreasing wave-lengths more rapidly than is shown by 

 the experiments. By giving the constants in formula (7) 

 another value, a closer agreement with the experimental 

 results may, of course, be easily obtained. Without dis- 

 cussing the theoretical assumptions which form the basis for 

 formula (7), I may state that it is evident that the relation 

 between the scattering coefficient and the wave-length can 

 be expressed by a function of that form. 



In order to be able to appreciate the magnitude of the 

 true absorption (k a X b ), the values found of /e a/ H 2 o f° r C, N, 

 and O have been corrected for scattering by deducting from 

 these values the products of 6, 7 , and 8 times tfH/H 2 o re- 

 spectively (Table VI.) . The remainders (A) thus found give 

 a measure of the true absorption at the wave-lengths used. 



It appears from the table that at the greater wave-lengths, 

 (I., II., & III.), the atomic absorption coefficients of C and N 

 are in very close proximity to, respectively, 6 and 7 times 

 ^h/h 2 o' l n ^ ne case °f the lightest elements, as far as N 

 nchisively, it seems that absorption can chiefly be considered 

 as a scattering effect, whereas true absorption seems to be 

 of very little account. Tiie difference between ko/h 2 o and 



