68 THE ABSORPTION SPECTRA OF SOLUTIONS. 



the exception of the last, represent the effect of adding potassium chlorate in 

 water and methyl alcohol. The last strip represents the effect of adding hydro- 

 gen peroxide. This spectrogram shows the almost complete disappearance of 

 the water bands, while the alcohol bands remain of about the same intensity. 



Plate 43, A, represents the absorption of uranous chloride in one part of 

 water and one part of methyl alcohol. Hydrogen peroxide, in equal volumes 

 of water and methyl alcohol, was added to this solution, three drops at a time; 

 except to the solution whose spectrogram is shown in the last strip, twelve 

 drops of hydrogen dioxide were added. The uranous alcoholate and hydrate 

 are oxidized to the same extent. 



Plate 43, B, represents the absorption due to uranous bromide 0.5 normal 

 in water, to which three parts of methyl alcohol were added. After a time a 

 precipitate was formed. This was filtered off, and strip 2 is the spectrogram 

 of the solution. Successive strips represent the effect of adding increasing 

 amounts of potassium chlorate in equal volumes of water and methyl alcohol. 

 Very little, if any, relative action manifests itself. 



A, plate 27, represents the absorption of concentrated nitric acid to which 

 increasing amounts of uranous chloride were added. 



B, plate 27, represents the absorption of the filtrate of a uranous bromide 

 solution. A solution of uranous bromide of sufficient strength when mixed 

 with alcohol to give the water and alcohol bands of the same intensity usualty 

 forms a precipitate if allowed to stand. Strip 1 shows the absorption of the 

 filtrate of such a solution, and indicates the selective precipitation of the 

 hydrate. The succeeding strips represent the absorption of uranous bromide 

 in water and alcohol, to which is added nitric acid in the same proportion of 

 water and alcohol. The last strip represents the solution containing the 

 greatest amount of nitric acid, to which was added a few drops of hydrogen 

 peroxide. 



C, plate 27, represents the absorption of uranous chloride in propyl 

 alcohol, to which acetone is added. A gives what we shall call the uranous 

 nitrate spectrum, although it is probably quite different from that of a neutral 

 aqueous uranous nitrate absorption spectrum. B is a good example of 

 selective precipitation, and of the action of nitric acid in increasing the inten- 

 sity of the hydrate bands at the expense of the alcoholate bands. C shows 

 how the addition of acetone causes the almost complete disappearance of the 

 uranous bands, and how, at the same time, the uranyl acetone bands appear 

 in place of the uranous bands. 



Plate 39, A, strip 1, represents the absorption of uranous chloride in 

 equal parts of water and methyl alcohol. Strip 2, the same, to which is added 

 a solution of sodium per chlorate in water and methyl alcohol. Strip 3 is a 

 corresponding strip when sodium perchlorate is replaced by potassium chlorate 

 in 4 parts of water and 3 of methyl alcohol. Strip 4 is the absorption 

 of a solution of uranous chloride in methyl alcohol and ether. Strips 2 and 

 3 show quite a strong selective action of these salts in increasing the relative 

 intensity of the alcohol bands. This action is especially marked in the case 

 of potassium chlorate. 



Plate 39, B, strip 1 , represents the absorption of uranous chloride in equal 

 parts of water and methyl alcohol, to which calcium nitrate is added; the 



