1909.] ' OF VARIOUS SALTS IN SOLUTION. 233 



a and h bands are affected entirely differently ; the a band being- very 

 much reduced in intensity and made narrower, whereas the b band 

 becomes very much stronger and wider. 



A new set of fine bands in the green has been discovered in the 

 absorption spectrum of an aqueous solution of uranyl chloride. 

 These only appear for pure water solutions ; a small amount of 

 aluminium or calcium chloride causing them to vanish. They do 

 not appear for methyl or ethyl alcohol solutions, and for no other 

 uranyl salt except very faintly for the sulphate. 



The absorption spectrum of several uranous salts has been 

 photographed. The spectrum is entirely different from that of 

 the uranyl compounds. The absorption spectra of uranous chloride 

 in methyl alcohol and in water were found to be very different. 

 The absorption spectrum of neodymium chloride in glycerol was 

 found to be entirely different from that of the salt in water. 

 Mixtures of water and glycerol seem to indicate the existence of 

 both sets of bands in the same solution. The " glycerol " bands are 

 more persistent with reference to water bands than " alcohol " bands 

 are. Much more work along this line is contemplated. 



Rise in temperature has been found in general to cause an in- 

 crease in the amount of absorption, and to cause the absorption 

 bands to widen. This widening of the bands may or may not 

 be symmetrical. 



Some of the absorption bands of uranous chloride widen very 

 rapidly with rise in temperature. Oilier bands do not widen so 

 rapidly, and seem to be slightly shifted towards the red. 



In solutions containing a single salt, it has invariably been found 

 that the bands widen with rise in temperature, and that this widen- 

 ing is greater, the greater the concentration of the solution. 



The uranyl bands of aqueous solutions of the chloride and sul- 

 phate of uranyl are shifted towards the red with rise in temperature. 

 The intensity of the uranyl bands does not seem greatly modified by 

 changes in temperature. 



The effect of rise in temperature on the absorption syectrum of 

 a solution of a salt containing calcium or aluminium chloride is 

 very peculiar. The bands usually broaden very unsymmetrically, 



