234 JONES-STRONG— THE ABSORPTION SPECTRA [April 24, 



and in all cases investigated, the widening has been on the longer 

 wave-length edge. A tyipcal example is shown in Plate III. 



Rise in temperature causes the neodymium bands to widen 

 slightly, but no shift of the bands has been noticed. However, 

 when calcium chloride has been added to the neodymium solution, 

 a rise of temperature causes many of the bands to become much less 

 intense, and also causes some of the bands to shift to the red. In 

 the recent work of Becquerel and others it is quite possible that the 

 presence of various foreign bodies in the crystals along with the 

 neodymium may have a very great influence upon the absorption 

 spectrum. 



All the above conclusions must be understood to be limited to the 

 conditions and within the ranges described in the earlier parts of 

 this paper. 



Physical Chemical Laboratory, 

 Johns Hopkins University, 

 May, 1909. 



