FROZEN SOLUTIONS. 



187 



The 1/1500 and 1/15,000 normal solutions yield bands which present 

 a hazy appearance, lacking the pronounced crests of the more con- 

 centrated solutions. For this reason the readings of such wave- 

 lengths are more likely to be in error. The same tendency to first 

 shift toward the violet and then shift toward the red is evident. 



TABLE 112. Uranyl potassium sulphate in water. 



The frequency interval, as may be seen from table 113, suffers a 

 marked change with dilution. The 1/15 and 1/150 normal solutions 

 show spectral series of 86.8 and 85.5 average interval respectively, 

 the 1/1500 series of 83.4 units, the 1/15,000 series of only 80.2 units. 

 The 1/1500 series undergo marked increase of interval on cooling. 



The bands of the 1/15,000 normal are so greatly shifted that they lie 

 approximately in the middle of the intervals between the bands of the 

 1/1500 normal solution. Such a "shift" of the entire spectrum must 

 be due to a marked change in the molecular arrangement ; hence it can 

 hardly be designated as a shift of the 1/1500 normal spectrum. Pre- 

 sumably a new hydrate has been formed by the freezing of the 1/15,000 

 normal solution. 



The 1/150,000 normal solution gave a spectrum which was too dim 

 to permit of measurement, except at the lowest temperatures. From 

 the three bands which are visible, it appears that the frequency interval 



