i9o8.; 



NEODYMIUM AND PRASEODYMIUM. 



279 



shading towards the red accompanying the band near A 5800, which 

 seems to decrease somewhat with dihition for concentrations of 

 one normal or less. 



In the following table the measurements of the positions of the 

 bands were made on the seventh strips of a, plate i, and, therefore, 

 refer to a concentration of 1.7 normal with a depth of layer of 24 

 mm. The remarks referring to changes with dilution apply to a 

 change in concentration from 3.4 to 1.7 normal, the depths of layer 

 being so varied that the product of concentration and depth remains 

 constant. 



4330 



4410-4465 



4580-4650 



4665-4710 



Hazy. 



Edges rather hazy. 



Band with hazy edges not 

 completely separated from 

 ^4665-^ 4710. 



]More sharply defined on red 

 than on violet side. 



The observed narrowing with 

 dilution perhaps due largely 

 to general U. V. absorption. 



Narrows slightly with dilution. 



Narrows some with dilution. 



Narrows considerably at first. 



Between this and ^4275 is 

 fairly strong absorption in 

 the most concentrated solu- 

 tion. This absorption has 

 disappeared in the spectrum 

 measured. 



This band is coincident with 

 band due to praseodymium, 

 and is to be ascribed to this 

 element w-hich has not been 

 completely separated from 

 the neodymium. It does not 

 change with dilution. 



Narrows slightly with dilution. 



Partly due to praseodymium. 

 Does not change with dilu- 

 tion. 



