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



absorption in the dilute solution, than it is for the concentrated solu- 

 tion previously described. 



The band AA.3455 to 3575 at 5° has widened slightly, having the 

 limits AA3445 and 3580 at 82°, the widening being about 15 

 Angstrom units. This band in the concentrated solution widened 60 

 Angstrom units. Practically no effect of temperature is to be 

 noticed upon the bands from A 4200 to A 4900 with rise in tempera- 

 ture. At the higher temperatures the bands are slightly more 

 diffuse, but this change is very small. The band AA 5020 to 5290 at 

 5° has widened to AA 5015 and 5285, about 10 Angstrom units. The 

 corresponding widening for the concentrated solution was approxi- 

 mately 50 Angstrom units, although it must be noted that in the 

 more concentrated solution this widening was mostly due to the 

 increased absorption of the band A 5310 at the higher temperatures. 

 The band A 5685 to A 5920 at 5° has widened to AA5775 and 5930, 

 about 20 Angstrom units, compared with a widening of 55 Angstrom 

 units for the more concentrated solutions. None of the other bands 

 show any appreciable change with change in temperature. 



A spectrogram (A, Plate XII.) was made showing the effect of 

 temperature upon the absorption spectrum of a 1.66 normal aqueous 

 solution of neodymium bromide, the depth of layer being 6 mm. 

 An exposure of 4 mm. was made to the Nernst glower, at .8 amperes 

 and a slit width of 0.20 mm. The length of exposure to the spark 

 was 6 mins. The temperatures of exposure, starting with the strip 

 adjacent to the comparison spark, were 4°, 20°, 36°, 50°, 68° and 



83°. 



At 4° there is complete absorption in the ultra-violet up to 



A 2600. A broad absorption band appears at A 2660 to A 2800 and 



from A 2950 to A3060. These absorption bands appear with a more 



or less general absorption. Bands appear at AA 3460, 3500 and 3540. 



The band at 4274 is weak. Weak and diffuse bands occur at 



AA4440, 4630, 4695, 4760, 4825, 5095, 5260, 6810 and 6900. Wider 



bands are located at AA5116 to 5140, AA 5200 to 5240 and AA5710 



to 5850. 



At 83° the spectrum is almost exactly the same as at 4°. The 



ultra-violet absorption is complete up to A 3050. The bands at 



A 3500 have increased in width slightly and the band A 4274 is 



