1909] OF VARIOUS SALTS IN SOLUTION. 215 



chloride in water was found to be very similar. The absorption 

 of the shorter wave-lengths was complete under the conditions 

 used. The following are the approximate positions of some of 

 the bands: AA,67oo, 6500, 6300, 5480 and 4900. The 6500 band 

 was the strongest one of all, and upon increasing the depth of cell 

 this band widened out so as to unite with the bands AA6700 and 

 6300, forming an absorption band covering hundreds of Angstrom 

 units. This is a very characteristic property of many of the 

 uranous bands, that of widening out so as to include a very large 

 portion of the spectrum. The uranyl bands do not change in 

 width very greatly on increasing the depth of cell. 



Besides the bands described above uranous chloride shows 

 bands at XX 4600, 4770 and 4970. 



The absorption spectrum of uranous chloride in methyl alcohol 

 was found to differ very much from that of the aqueous solution. 

 The bands at AA4600 and 4780 appeared, closely resembling the 

 water bands at the same position. The band A 4970 in water was 

 broken up into two bands in methyl alcohol at AA4930 and 5030. 

 In the alcohol a very broad band appeared at A 5300, which does 

 not appear at all in the water solution. The band at A 5580 is very 

 similar to the water band. Weak and broad bands appear at 

 AA6150, 6300 and 6480, and a strong band at A 6750. As the depth 

 of the alcoholic solution is increased the widening of the bands 

 is very different from the widening of the bands of the aqueous 

 solution. 



The absorption spectrum of a mixture of calcium chloride and 

 uranyl chloride in water was found to be very similar to that of 

 the pure uranyl water solution. Much further work along the 

 above lines is being carried on. 



VIII. An Example of the Complexity of the Problem of 



Explaining the Origin of Spectral Lines and Bands 



AND the Proposed Method of Attack. 



It is a fact that investigations upon the spectral emission and 

 absorption of bodies has been far less fruitful in extending our 

 knowledge of the structure of the atom than had been expected. 



