ROENTGEN ABSORPTION HISTOSPECTROSCOPY 



139 



absorption in very small areas. The latter method was previously 

 described in connection with Caspersson's absorption technique for 

 cells (page 114) and Norberg's technique for fluids (page 120). 



1.00 

 0.90 

 0.80 

 0.70 

 0.60 



0.50 

 0.40 



030 



0.20 



—I 0.01 



0.10 

 0.09 

 0.08 

 0.07 

 0.06 



0.05 

 0.04 



003 - 



X = 





H 



Mi _ t^(h\' 



p P \X2/ 



Ml 

 P 



^lg/mm^ 



0.02 



0.01 



//g/mm.^ 



26 Fe 100 ^g/mm." 



20 Ca 40 



0.02 



0.03 



0.04 



0.05 



0.06 



0.07 



0.08 

 0.09 ^ 



0.10 ■^-- 



Fig. 28. Nomogram for calculating analytical results by equation 



From Engstrom (1946) 



0.20 



030 



040 



0.50 



0.60 

 0.70 

 080 

 0.90 

 — ' 1.00 



shown. 



The light absorption in areas less than 1 fi^ can be accurately 

 measured with this apparatus; however, the size of the grains, 

 even in the finest films, makes it necessary to measure the blacken- 

 ing in areas 10 X 10 fi. 



