80 THE ABSORPTION SPECTRA OF SOLUTIONS. 



The general result of rise in temperature is to cause a large increase in the 

 general absorption in the ultra-violet. This is especially strong at 120, where 

 the general absorption is complete to about X 4100, and extends as a partial 

 absorption to beyond X 5000. The neodymium bands are considerably 

 widened by rise in temperature, and are shifted in man}' cases some 15 or 20 

 Angstrom units towards the red (120 compared with 20). 



Some of the more pronounced changes may be noted if the following 

 wave-lengths are compared with those described under the chapter on map- 

 ping of spectra. At 1 20 a weak band appears at X 4260. It is about 10 

 Angstrom units wide. The other bands of the /3 group are at X 4295, X 4305, 

 X 4325, and X 4360. The lines of the y group are at X 4725, X 4775, and 

 X 4850. The 8 group consists of the wide band at X 5140 and the double band 

 at X 5250 and X 5275. The e group runs from X 5720 to X 5960 as a single band. 



Neodymium Nitrate in Acetone. 



A spectrogram was made of the absorption spectrum of a solution of 

 neodymium nitrate in acetone, in the long cell, at 16, 40, 70, 100, and 180. 

 The solution became opaque at about 110, and afterwards quite transparent 

 at about 160. 



The effect of the rise in temperature was to cause a slight shift of the 



neodymium bands to the red, but as these bands were so very broad and hazy, 



no measurements could be made. The strip taken at 180 shows a very great 



absorption in all regions except the yellow and red, and the absorption in the 



red is, indeed, almost complete. There is no indication of any neodymium 



bands at all, so that it seems that practically all the neodymium nitrate had 



been precipitated. 



Erbium Chloride in Water. 



A, plate 60, represents the spectrum of an aqueous solution of erbium 

 chloride at 20, 30, 85, and 115 C. 



The effect of rise in temperature on the individual erbium bands is very 

 small, their diffuseness being hardly increased with rise in temperature. The 

 increase in the general absorption throughout the region of smaller wave- 

 lengths is enormous, resulting in the solution being practically opaque at the 

 higher temperatures. 



Strip 1 shows the following bands, the wave-lengths being only approxi- 

 mate: a band from X 3430 to X 3520; a strong band at X 3540 which is about 

 10 Angstrom units wide; weak bands at X 3555, X 3570, and X 3595; the previous 

 band is the beginning of a region of absorption that extends to X 3660; a 

 group of three bands that practically merge into a single band running from 

 X 3750 to X 3790; weak bands at X 3800 and X 3840; diffuse bands at X 3870; 

 strong X 3900, X 3950 weak, X 4000 weak; X 4045 sharp and narrow (10 units); 

 X 3070 sharp and narrow; X 4100 very weak; XX 4155, 4165, 4185, 4215 these 

 bands are much alike, the first being the most intense; X 4270 is wide and very 

 weak; X 4430 diffuse; X 4450 very weak; X 4480 weak; X 4500 strong; X 4530 is 

 apparently covered by a diffuse band on its red side; X 4685 weak; X 4750 and 

 X 4800 wide and weak; X 4855 narrow; X 4880 intense; X 4930 probably double; 

 X5200; X5225; X 5245 intense; X 5290 weak; X5380; X 5390 weak; X 5435; 

 X 5455; X 5520 weak; group at X 5770 very weak; X 6440, X 6460, X 6530, X 6560 

 strong. X 6600 and X 0710 all very diffuse and having a very "washed-out" 

 appearance. 



