AS MEASURED BY MEANS OF THE RADIOMICROMETER. 



77 



In column 1 there is given X taken at such intervals as the graduated head of 

 the spectroscope would permit. Reading from left to right, the respective 

 concentrations were 1.377, 0.688, 0.344, and 0.177 normal, the corresponding 

 depths of absorbing layer being 2.5, 5, 10, and 20 mm., respectively. 



Table 16. Percentage Transmissions of Praseodymium. Chloride Solutions. 



In terms of Beer's law, the curves representing these tables should be iden- 

 tical. Such curves are represented by fig. 34. Beginning with the curve 

 nearest the left and proceeding towards the right, the succeeding curves rep- 

 resent the four dilutions of praseodymium chloride as given in the preceding 

 paragraph. 



100 



o 



I/} 



i/> 



Z 

 < 

 01 



t 



L|J 



<J 



I 

 z 



UJ 



<_> 



IE 



75 



50 



25 



Cell Depth 2.5 mm. 

 Concentration I.377N 



Cel, Depth 5 mm. 

 Concentration 0688N 



Cell Depth 10 mm. 

 Concentration 0344 N 



Cell Depth 20 mm. 

 Concentration 0.177 N 



0.55/^ 



0.6/7 0.55u 



0.6/7 0.55/y 



Fig. 34. 



0.6/7 0.55/^ 



0.6/7 



The curve representing the most concentrated solution is nearest the left 

 of the figure. It is seen that these curves are identical to within the limits of 

 experimental error; the slight increase in the absorption with dilution is to 

 be attributed to the slit-width correction. The slit-width was in every case 

 0.4 mm. Water has no absorption in this region. 



