104 



DESCRIPTION OF PLATES. 



Plate 23. A 



B. 



Plate 28. 



B. 



C. 

 A. 



B 



Plate 29. A 



B. 



Plate 30. A. 

 B. 



Plate 31. A. 



B. 



Plate'32. A, 



B. 



Uranous Bromide in Water to which Methyl Alcohol is added. This spec- 

 trogram shows the great difference between the water and methyl alco- 

 hol bands of uranous bromide. 



Uranous Chloride in Water to which Methyl Alcohol is added. The methyl 

 alcohol was added in smaller quantities than to the solutions whose 

 spectrograms are recorded in the above plate. 



Uranous Chloride in Methyl Ester to which Water is added. 



Uranous Chloride in Methyl Ester. Depth of cell is gradually increased. 



Uranous Chloride in Ethyl Ester. Depth of cell variable. 



Uranous Acetate in Acetone. Depth of cell variable. 



Uranous Chloride in Ether. Depth of cell variable. 



Uranous Chloride in Acetone. Depth of cell variable. 



Uranous Chloride in concentrated Nitric Acid. The uranous chloride is 

 added to the acid which was placed in the Uhler cell. It is very remark- 

 able that the uranous salt is not oxidized under these conditions. 



Uranous Bromide in Water and Methyl Alcohol after the precipitate has 

 been filtered off (strip 1). This shows a selective precipitation of the 

 hydrate. The succeeding strips show the absorption of uranous bromide 

 in water and methyl alcohol to which increasing amounts of nitric acid 

 (in the same proportion of water and alcohol) are added. 



Uranous Chloride in Propyl Alcohol to which Acetone is gradually added. 



Gadolinium Chloride in Ethyl Alcohol. Concentration constant, 0.8 normal. 

 Depths of cell, starting with the lowest strip, 2, 4, 9, 18, 27, and 27 mm. 

 In the upper strip an exposure was made directly to the ultra-violet spark 

 fines. 



Gadolinium Chloride in Water. Concentration constant, 1.407 normal. 

 Depths of cell, starting with the lowest strip, 2, 10, 15, 22, 22, and 100 mm. 

 In the upper two strips an exposure was made directly to the ultra-violet 

 spark lines. 



Dysprosium Chloride in Methyl Alcohol. Concentration about normal. In 

 all the spectrograms of gadolinium, dysprosium, and samarium, the slit 

 width was 0.10 mm., the current in the Nernst glower 0.9 ampere, and 

 the length of exposure was 1 minute to the visible portion of the Nernst 

 glower spectrum, and about 5 minutes to the ultra-violet part of the 

 Nernst glower spectrum. The depths of cell were 1, 5, 12, 20, 31, and 

 31 mm. The upper strip was exposed directly to the ultra-violet spark lines. 



Dysprosium Chloride in Water. Concentration, 1.86 normal. Depths of 

 cell, starting with lowest strip, 2, 6, 10, 15, 21, and 100 mm. All the 

 strips except the lowest one were exposed directly to the ultra-violet spark 

 lines. 



Dysprosium Chloride in Water. Concentration, 1.86 normal. Depths of 

 cell, starting with lowest strip, 2, 8, 16, and 21 mm. 



Dysprosium Acetate in Water to which varying amounts of Nitric Acid 

 were added. Concentration of the neutral solution, 0.4 normal. The in- 

 creased depth of cell is due to the addition of concentrated nitric acid. 

 Starting with the lowest strip the depths of cell were: 15, 15.1, 15.3, 15.7, 

 16.7, and 32 mm. 



Dysprosium Acetate in Water. Concentration, 0.4 normal. Depths of cell, 

 starting with lowest strip, 4, 16, 25, and 34 mm. Exposures were made 

 in strips 2, 3, 5 directly to the ultra-violet spark lines. 



Dysprosium Chloride in Ethyl Alcohol. Concentration, 0.74 normal. Dept hs 

 of cell, 2, 10, 15, 24, 30, and 30 mm. The upper si rip was exposed directly 

 to the ultra-violet spark lines. 



Samarium Chloride in Water. Concentration, 1.31 normal. Depths of 

 cell, starting with lowest strip, 2, 6, 12, 16, 20, and 100 mm. Strips 'A, 4, 

 5, <) were exposed directly to the ultra-violet spark lines. 



Samarium Chloride in Methyl Alcohol. Concentration about normal. 

 Depths of cell, 2, 5, 9, 18, 27, and 27 mm. The upper strip was exposed 

 directly to the ultra-violet spark lines. 



