DESCRIPTION OF PLATES. 27 



10. A. Uranyl Nitrate in Water. Concentration, 0.2 normal. Cell depth, 1 cm. 



Temperatures, starting with strip nearest spark lines, were 20, 40, 60, 

 80, 100, and 120, respectively. 

 B. Uranyl Nitrate in Water. Concentration, 0.02 normal. Depth of cell, 10 cm. 

 Temperatures, starting with exposure nearest spark lines, were 20, 45, 

 70, 95, 115, 140, and 165, respectively. 



11. A. Uranyl Sulphate in Water. Concentration, 0.166 normal. Depth of cell, 1 cm. 



' Temperatures, beginning nearest spark lines, 20, 45, 70, 90, 115, 135, 

 155, and 185, respectively. 

 B. Uranyl Sulphate in Water. Concentration, 0.02 normal. Cell depth, 10 cm. 

 Respective temperatures, beginning nearest spark lines, were 20, 45. 70, 

 95, 115, 140, and 165. 



12. A. Uranyl Acetate in Water. The concentrations, beginning with the strip most 



removed from the numbered scale, were 0.25, 0.125, 0.062, 0.042, 0.0025, 

 0.0005 normal, respectively; the corresponding depths of absorbing layer 

 were 0.5, 1, 2, 3, 50, and 250 cm. 

 B. Uranyl Acetate in Water. Concentration, 0.02 normal. Depth of cell, 10 cm. 

 The temperatures, beginning with the strip nearest the numbered scale, 

 were 20, 45, 70, 95, 115, and 140, respectively. 



13. A. Neodymium Chloride in Water. Concentrations, 2.05, 0.0205, and 0.00401 nor- 



mal. Respective depths of cell, 0.5, 50, and 250 cm. Most dilute solution 

 nearest spark lines. 



B. Neodymium Chloride in Water. Concentrations, 1.025, 0.01025, and 0.00205 



normal. Depths of cell, starting with strip farthest from spark lines, 

 were 0.5, 50 and 250 cm., respectively. 



C. Neodymium Chloride in Water. Concentrations, 0.512, 0.00512, and 0.00102 nor- 



mal. Depths of cell, beginning with strip farthest removed from spark 

 lines, were 0.5, 50, and 250 cm., respectively. 



14. A. Neodymium Bromide in Water. Concentrations, 1.66, 0.0166, and 0.0033 normal. 



Corresponding depths of cell, 0.5, 50, and 250 cm., respectively. Most 

 dilute solution nearest spark lines. 



B. Neodymium Bromide in Water. Concentrations, 0.83, 0.0083, and 0.00166 



normal. Corresponding depths of cell, 0.5, 50, and 250 cm., respectively. 

 Most dilute solution nearest spark lines. 



C. Neodymium Bromide in Water. Concentrations, 0.415, 0.00415, and 0.000S03 



normal. Corresponding depths of cell, 0.5, 50, and 250 cm., respectively. 



15. A. Neodymium Nitrate in Water. Concentrations, 2.15, 0.0215, and 0.00430 normal, 



respectively. Corresponding depths of cell were 0.5, 50, and 250 cm., 

 respectively. Most dilute solutions nearest spark lines. 



B. Neodymium Nitrate in Water. Concentrations, 1.075, 0.01075, and 0.00215 



normal. Corresponding cell depths were 0.5, 50, and 250 cm., respectively. 



C. Neodymium Nitrate in Water. Concentrations, 0.537, 0.00537, and 0.00107. 



Corresponding depths of cell were 0.5, 50, and 250 cm., respectively. Most 

 dilute solutions nearest spark lines. 



16. A. Neodymium Acetate in Water. Concentrations, 0.5, 0.01, and 0.002 normal; 



the corresponding depths of absorbing layers being 0.1, 50, and 250 cm., 

 respectively. 



B. Neodymium Sulphate in W T ater. Concentrations 0.1, 0.004, and 0.0008 normal, 



the corresponding depths of cell being 2, 50, and 250 cm., respectively. 



C. Neodymium Sulphate in Water. Concentrations, 0.1, 0.001, and 0.0002 normal. 



Depths of cell, 0.5, 50, and 250 cm., respectively. In each case, the most 

 dilute solution is nearest the numbered scale. 



17. A. Neodymium Acetate in Water. Concentrations, saturated, 0.01s and 0.002s, 



where s represents a saturated solution of the salt in water at 25. Corre- 

 sponding depths cf cell were 0.5, 50, and 250 cm., respectively. 



B. Neodymium Acetate in Water. Concentrations, 0.50s, 0.005s, and 0.001s (s being 



a saturated solution as above). Corresponding depths of cell were 0.5, 

 50, and 250 cm. 



C. Neodymium Acetate in Water. Concentrations, 0.25s, 0.0025s, and 0.0005s. 



Corresponding depths of cell were 0.5, 50, and 250 cm., respectively. 



18. A. Praseodymium Chloride in Water. Concentrations, 2.56, 0.0256, and 0.00512 



normal, respectively. Corresponding depths of cell were 0.5, 50, and 250 cm. 



B. Praseodymium Chloride in Water. Concentrations, 1.28, 0.0128, and 0.00256 nor- 



mal. Corresponding depths of cell were 0.5, 50, and 250 cm., respectively. 



C. Praseodymium Chloride in Water. Concentrations, 0.64, 0.0064, and 0.00128 nor- 



mal. Corresponding depths of cell were 0.5, 50, and 250 cm., respectively. 



