URANIUM SALTS. 103 



absorption to be very much more intense. The bands are shoved towards 

 the violet. The a band, X 4790, is made very weak, the b band, X 4670, 

 narrow and strong, the c band, X 4510, the d band, X 4370, and the e band, 

 X 4230, are quite strong. The other bands, /, X 4125, g, X 4000, h, X 3900, 

 i, A 3790, /, A 3670, and k, X 3570, are rather weak, the latter two being 

 stronger, however, than in the corresponding aqueous solution. 



When the depth of layer is sufficient so that the whole shorter 

 wave-length portion of the spectrum is absorbed to X 4850, it is found that 

 the whole region of the spectrum remaining is filled with a multitude of 

 extremely fine absorption lines. 



This fine band absorption spectrum is that of nitric oxide. 



Uranyl Nitrate in Methyl Alcohol. 



In a spectrogram the depth of cell was kept constant at 15 mm.; the 

 concentrations, beginning with the strip nearest the scale, were .20, .158, 

 .124, .10, 0.079, 0.063, and 0.05 normal. Exposure was made to the Nernst 

 glower for 1 minute with the current at 0.8 ampere. The corresponding 

 limits of absorption are XX 4800, 3750, 3700, 3650, 3600, 3550, and 3500. 

 Two of the smaller bands, a and b, appear at the lower concentration. 

 These bands are about 30 Angstrom units wide and their positions are 

 XX 4920 and 4745. 



Plate 67, B, represents the same concentrations, 0.2 normal, as Plate 

 54, A. Here the depth of cell is kept constant at 3 mm. The spectro- 

 gram shows the characteristic blue-violet band and the ultra-violet band. 

 For concentration 0.2 normal, the positions of the edge of the ultra-violet 

 band are XX 3825, 3800, 3770, 3750, 3720, 3700, and 3670. 



The blue-violet band for 0.2 normal solution has the limits X 4470 and 

 X 3825. The middle of this band thus comes at about X 4150; exactly where 

 the band for water is situated. The concentration when the same band 

 fades out for water is 0.5 normal, whereas for alcohol it is much less, show- 

 ing that uranyl salts in alcohol are much more deeply colored than in water. 

 The following are the wave-lengths of the small bands: a, X 4930; b, X 4760; 

 c, X 4610; d, A 4460; e, X 4325; /, X 4190; g, X 4070; h, X 3970; i, A 3855. 



For Plate 67, A, the Nernst glower was run 1 minute at 0.8 ampere, 

 slit-width 0.08 mm. Starting with the comparison spectrum the concentra- 

 tions were normal 0.2, 0.16, 0.126, 0.1, 0.08, 0.063, and 0.033, the corre- 

 sponding depths of solution being 6, 7.5, 9.5, 12, 15, 19, and 24 mm. Uranyl 

 nitrate in methyl alcohol shows very marked deviations from Beer's law, 

 the absorption being much greater where the concentrated solutions are 

 used. The limits of absorption for concentrations 0.2, 0.16, 0.126, 0.1, 

 0.0S, 0.063, and 0.033 normal are, respectively, XX 4720, 4700, 4680, 4660, 

 4650, 4640, and 4630. 



Uranyl Nitrate in Methyl Alcohol and Water. 



In the previous work of Jones and Anderson it was found that in the 

 case of neodymium salts the absorption spectrum was very often different 

 in pure alcohol from what it was in pure water. This fact had been noticed 

 before by several observers, and had been believed by some to be due to the 



