CHEMISTRY — JONES. 2I3 



change either in width or position. In a word, it is only necessary to keep 

 the product of concentration and depth of cell constant. It was found that 

 Beer's law holds for all four of the above-named potassium compounds. 

 This would be expected, since no one of these compounds crystallizes with 

 any large amount of water and is therefore not largely hydrated in solution. 



The following uranyl salts were brought within the scope of this work: 

 chloride, bromide, nitrate, sulphate, and acetate. The absorption spectra of 

 all of these salts in aqueous solution were studied ; also the chloride and 

 nitrate in solutions in methyl and ethyl alcohols. Beer's law was found to 

 hold for all dilute solutions of these salts. There were deviations from 

 Beer's law in the more concentrated solutions in water of uranyl nitrate and 

 sulphate ; these solutions showing greater absorption than would be expected 

 if Beer's law holds. Uranyl acetate, on the other hand, showed in concen- 

 trated solutions less absorption than would be expected from this law. This 

 is the only salt thus far studied which deviated in this direction from the law. 



This same salt in methyl alcohol shows the same kind of a deviation from 

 Beer's law, but not to the same extent. 



The absorption spectra of uranyl salts were found to show 12 bands in the 

 blue-violet portion of the spectrum ; 2 of these having never been observed 

 before. Several new and very fine bands were found in the aqueous solutions 

 of uranyl chloride; these bands disappear when calcium or aluminium chlo- 

 ride is added to the aqueous solution ; they do not appear at all in the alcoholic 

 solutions and may be "water" bands. 



Some interesting results were obtained in reference to the positions of the 

 uranyl bands. The uranyl nitrate bands are all shifted towards the violet 

 with respect to the bands of the other uranyl salts. The uranyl nitrate bands 

 in methyl alcohol and ethyl alcohol are shifted towards the red. 



The addition of calcium chloride or aluminium chloride to aqueous solu- 

 tions of uranyl chloride shifts the bands towards the red. The addition of 

 calcium chloride to a methyl alcohol solution of uranyl chloride does not pro- 

 duce any shift in the bands. Hydration thus undoubtedly has much to do 

 with the shift of these bands. 



As will be seen, rise in temperature shifts the bands of uranyl chloride and 

 uranyl sulphate towards the red. 



The absorption spectra of uranyl chloride in water to which aluminium 

 chloride is added is practically the same as the absorption spectra of uranyl 

 chloride in ethyl alcohol. 



The absorption spectra of uranyl chloride in methyl alcohol shows that the 

 bands are shifted toward the red with respect to the bands in the aqueous 

 solution. When calcium chloride is added to the methyl alcohol solution of 

 uranyl chloride the spectrum is very similar to that of uranyl chloride in 

 ethyl alcohol. 



