The Absorption Coefficient of Solution for Monochromatic Radiation. 37 



The pure-alcohol solution was a deep purple, changing by successive 

 stages to pink as the concentration of the water increased. The fourth 

 solution, for which c 2 = 8.32, was very nearly the same color as the 

 pure-water solution. These mixtures decomposed upon standing, 

 in a manner similar to the pure-water solutions, yielding a flocculent 

 precipitate. 



TABLE 11. Cobalt Chloride in Methyl Alcohol vrith Water (Fig. 11). 



The absorption curves have not been plotted. From each value of 

 a has been subtracted the absorption a , due to the solvent. The 

 value of a has been calculated from the known amounts of water and 

 alcohol present in the solution. The values of a a have been plotted 

 as ordinates against wave-lengths as abscissas. These are the curves 

 which appear in figure 11. These curves show the well-known sub- 

 siding of the edge of the red absorption band as the amount of water 

 present in the alcoholic solution increases; also that the edge of the 

 infra-red band, between 978jujLt and 1,134^, is practically the same in 

 methyl alcohol as in water solutions, and hence is uninfluenced by the 

 addition of water to the methyl-alcohol solution. 



COBALT CHLORIDE IN ETHYL ALCOHOL WITH WATER. 



Five ethyl-alcohol solutions were prepared containing cobalt chloride 

 and water. The concentration of the cobalt chloride, denoted by Ci 

 in table 12, was 0.08 for each solution. The concentrations of the 

 water, denoted by c 2 , were 1.29, 2.78, 4.16, 5.55, and 6.94. The values 

 of a for the pure-alcohol and pure-water solutions were interpolated 

 from the work on cobalt chloride in these solvents. 



