URANIUM SALTS. 



113 



contrast with many of the plates in which there are certain stages that 

 hardly show any uranyl bands at all, whereas at other stages the bands 

 will be very strong indeed. 



The bands in the upper strips beyond the region X 5000 are probably 

 due to nitric oxide. Several of the bands are quite strong. 



The simplest interpretation of this plate is that as more and more 

 sulphuric acid is added molecules are formed that contain more and more 

 of the acid. That there are several of these compounds formed seems 

 probable, since the shift of the bands is quite large and this shift takes 

 place gradually. 



Plate 83, A, gives the effect of adding sulphuric acid to an aqueous 

 solution of uranyl nitrate. The first strip here gives the absorption of 

 uranyl nitrate to which no acid has been added. The changes here are 



8 



