102 



DESCRIPTION OF PLATES. 



Plate 7. ^4. Neodymium Chloride in Propyl Alcohol. Depth of cell constant, 30 mm. Con- 

 centrations, starting with lowest strip, 0.04, 0.03, 0.02, and 0.0133 normal. 

 B. Neodymium Nitrate in Propyl Alcohol. Depth of cell constant, 16 mm. 

 Concentrations, starting with lowest strip, 0.05, 0.07, 040, 0.15, 0.225, 

 and 0.3 normal. 

 Plate 8. A. Neodymium Chloride in Isobutyl Alcohol. Depth of cell constant, 34 mm. 

 Concentrations, starting with lowest strip, 0.024, 0.018, 0.012, and 0.008 

 normal. 

 B. Neodymium Nitrate in Isobutyl Alcohol. Depth of cell, 16 mm. Concen- 

 trations, starting with lowest layer, 0.05, 0.07, 0.10, 0.15, 0.225, and 0.3 

 normal. 

 Plate 9. A. Neodymium Nitrate in Butyl and Isobutyl Alcohols. Strip 1 is a 3 mm. 

 and strip 2 a 13 mm. layer of a 0.3 normal solution in butyl alcohol; 

 strip 3 is a 3 mm. and strip 4 a 13 mm. layer of a 0.6 normal solution in 

 isopropyl alcohol. 

 B. Neodymium Nitrate in mixtures of Ethyl and Isobutyl Alcohols. Depth of 

 cell constant, 34 mm. Concentration constant, 0.1 normal. Starting 

 with lowest strip the percentages of the solvents were: 

 20, 40, 60, 80, 100 ethyl alcohol. 

 80, 60, 40, 20, isobutyl alcohol. 

 Plate 10. A. Neodymium Nitrate in Methyl Ester. Depth of cell constant, 18 mm. 

 Concentrations, starting with lowest strip, 0.05, 0.07, 0.10, 0.15, 0.225, 

 and 0.3 normal. 

 B. Neodymium Nitrate in Ethyl Ester. Depth of cell constant, 18 mm. Con- 

 centrations, starting with lowest strip, 0.05, 0.07, 0.10, 0.15, 0.225, and 

 0.3 normal. 

 Plate 11. A. Neodymium Nitrate in Anthracene and Ethyl Acetate. The variable quantity 

 here is depth of cell. The early investigators made experiments to test 

 whether two colored salts in the same solvent having bands that were of 

 almost the same wave-lengths had the wave-lengths of these bands changed 

 with reference to the wave-lengths of the bands for the solutions of the 

 separate salts. At present this would hardly be expected to result, unless 

 double solvates were formed, i.e., compounds containing the two salts 

 and the solvent. This spectrogram was taken to find whether the 

 anthracene and neodymium bands had their wave-lengths affected by 

 both being dissolved in ethyl ester. This might be expected if compounds 

 were formed containing both anthracene and neodymium nitrate. The 

 ' bands are in the ultra-violet. Unfortunately it is very difficult to obtain 

 the anthracene and neodymium bands together. 

 B. Neodymium Nitrate in Ethyl Acetate and Anthracene. To obtain this 

 spectrogram it was necessary to heat the solutions in order to keep the 

 anthracene in solution. The percentages of anthracene for the 6 strips, 

 starting with the lowest, were: 0.25, 0.5, 0.75, 1, 1.5, and 2. 

 Plate 12. A. Neodymium Nitrate in Ethyl Acetate and Anthracene. Concentration of 

 neodymium nitrate, 0.24 normal. Succeeding strips show the effect of 

 adding ethyl alcohol, methyl alcohol and acetic acid, respectively. 

 B. Neodymium Nitrate in Ethyl Acetate and Anthracene. The lowest strip 

 is the only one that shows the anthracene bands. 

 Plate 13. A. Neodymium Acetate in Formamide. The acetate slowly decomposes, form- 

 ing a white precipitate. Strips 1 and 2 represent different depths of cell 

 (strip 2 being 35 mm.). Strip 3 is the same as 2 after water has been 

 added. The original film shows quite a large shift of the neodymium 

 bands towards the violet in the upper strip, compared with the second strip. 

 B. Uranyl and Uranous Sulphates in Water, to which Acetic Acid is added. 

 Starting with strip 1 increasing amounts of acetic acid are added to an 

 aqueous solution of uranyl sulphate. This results in a precipitate (strip 

 5), and the solution is filtered and the absorption spectra again taken 

 (strip 6). Strips 7 and 8 represent the uranous salt formed from the solu- 

 tion used for strip 6 when zinc is added. 



