the Absorption of X-Rays. 201 



said above, it is admitted that 



p 



K a/CM = 



K+Pa9 



/* M 100+ PCn^ 



~Ou iU Cu 

 r 

 or 



A* - M Cu • K « /* Mcu^gg f* nfi x 



p a - M a (100 +Pcu g) ^ Cu + M B (100 + Pcn q) ~p c » ; ' ^ 



and as - = A\ 6 4--, then will 

 P P 



p-M a (ioo+p Cxi qy p c »> ■ • • • (i ' ; 



or as g^Q u = 0*()78 and p Cu <7 is supposed to be negligible, 



P 



M 



£=-,£. p.. "0;00678 (18) 



In the following table we again find the mass scattering 

 coefficients for the elements 1-20, calculated by the 

 formula (18) . 



Table XIV. 

 Mass scattering coefficients for the elements 1-20. 



Atomic 





Number of 



-, calculated 



according to 



number. 



Element. 



outer electrons. 



P 





Z. 



formula (18). 



formula (19) 



1 



H 



1 



0-432 



0-205 



3 



Li 



3 



0-187 



0205 



4 



Be 



4 



0-190 



0-205 



5 



B 



5 



0-196 



0-205 



6 



C 



4 



0-144 



0-137 



7 



N 



7 



0216 



0-205 



8 







4 



0-108 



0-103 



9 



F 



5 



0-114 



0-114 



11 



Na 



7 



0-132 



0-130 



12 



Mg 



4 



0-071 



0-068 



13 



Al 



5 



0-080 



0-079 



14 



Si 



4 



0-061 



0-059 



15 



P 



7 



0-097 



0-096 



16 



S 



4 



0052 



0-051 



17 



CI 



5 



0-061 



0-060 



19 



K 



7 



0-077 



0-076 



20 



Ca 



4 



043 



0041 



