R&ntgen Radiation in Air. 613 



get a straight line for each homoo-eneous constituent. Let 

 us draw three arbitrary lines. P 1? P 2 . *3 • Pi representing a 



rapidly absorbed, strongly ionizing radiation, and P 3 a radia- 

 tion of small ionizing power in comparison, and absorbed 

 more slowly. On adding the real lengths of these ordinates, 

 and plotting on the logarithmic paper, we get the Curve I. 

 Xext we assume that P x is not represented at all in the 

 secondary, that P 2 is represented unchanged, except for the 

 diminution in intensity and that P ?) is transformed into a 

 more absorbable radiation, i. e.* a line S 3 which is steeper 

 than P 3 . The ordinates of S 2 and S 3 added give the Curve II. 

 In Curve III. the ratios of corresponding ordinates of II. to 

 those of I. are plotted as ordinates, the abscissa? being the 

 same as before. Up to the point h this curve shows the same 

 features as Curve III., fig. d, but the portion a is much 

 exaggerated. If we had assumed that P 3 was scattered instead 

 of being transformed, i. e. that P 3 and S 3 were identical, the 



