88 



A STUDY OF THE ABSORPTION SPECTRA. 



tains 80 per cent alcohol all the bands are shifted towards the violet, and 

 for a pure alcohol solution all the uranyl bands are of shorter wave-length 

 than for a pure aqueous solution. 



Deussen obtained very interesting results for uranyl nitrate in mixtures 

 of water and glycerol. As the percentage of glycerol increases the c and d 

 bands broaden and finally, for a pure glycerol solution, form but a single 

 band. At the same time all the other bands are shifted towards the red. 



URANYL CHLORIDE. 



For uranyl chloride solutions in mixtures of water and glycerol, Deus- 

 sen finds that the c band of the aqueous solution breaks into two bands 

 when the solvent is pure glycerol. Increasing percentages of glycerol cause 

 an increased shift of the bands towards the red. 



URANYL SULPHATE (U0 2 S0 4 .3H 2 0). 



H. Becquerel 1 has made a number of observations on the absorption 

 spectra of uranium compounds at low temperatures. He considers that 

 the absorption and phosphorescent bands are parts of a single system. 

 They have two bands in common. He states that any modification in the 

 appearance of one set of bands for any compound is reproduced by a similar 

 change in the other set of bands. In general, the bands found at the tem- 

 perature of liquid air are moved towards the violet with respect to the same 

 bands at ordinary temperatures. Uranyl nitrate, at ordinary tempera- 

 tures, gives wide diffuse bands whose intensities are at a maximum at 

 their middle. At the temperature of liquid air each group is resolved into 

 several centers, and the most intense of these bands are towards the violet. 

 A table of the wave-lengths of these bands is given below. 



Bois and Elias 2 find that the double sulphate of uranyl and potassium 

 when cooled to - 190 gives bands at XX 4878, 4882, 4888, and 4905. These 

 seem to broaden slightly when placed in a strong magnetic field. At 18 

 uranyl nitrate gives bands at X 4675-4716, X 4849-4880, and at - 190 C. 

 strong bands at X 4679-4697, X 4845-4849, and X 4853-4857. 



Uranous salts are of a deep green color and have a very characteristic 

 absorption spectrum, which consists of diffuse bands scattered throughout 



'Compt. rend., 101, 1252 (1885); 144,459, 671 (1907). 

 2 Ann. Phys., 21, 299 (1908). 



