562 



WICK. 



observation chamber to about 1.4 cm. and it was possible to vary only 

 the concentration of the solution in order to bring out different bands. 

 The exact concentration of solution used was not known except in 

 the case of neodymium ammonium nitrate solutions which varied 

 from .0698 to .693 normal. 3 



The position and width of the absorption bands in dilute solutions 



A-QQQ . 



5000 6000 



Wave length m Angstrom Units 



Absorption spectrum of aqueous neodymium cliloriiie (Keih , tbiokness of absorbing layer = 20 cms.). 



Figure 3. 



of neodymium salts for different concentrations are shown in Figure 3 

 taken from the work of Rech 4 and copied directly from Little's 5 book. 

 Along the horizontal axis, the width of the various absorption bands 

 in Angstrom units is indicated for different concentrations whichare 



3 The term "normal solution" is used to indicate one that contains the 

 same number of grams of solute per liter of solvent as the number which repre- 

 sents the molecular weight of the salt dissolved. 



4 Rech, Zeits. Wiss. Photochem., 1905, 3, 411. 



5 Little, Text-book of Inorganic Chemistry, Vol. IV, p. 290. 



70M 





