The Absorption Coefficient of Solution for Monochromatic Radiation. 39 

 TABLE 12. Cobalt Chloride in Ethyl Alcohol with Water (Fig. 11). 



The a a curves (see paragraph on cobalt chloride in methyl alcohol 

 with water, p. 36) show that as the amount of water present in the 

 ethyl-alcohol solution increases the absorption at the edge of the red 

 band becomes less, and also that the edge of the infra-red band behaves 

 in a similar manner. The behavior of the infra-red band in the ethyl- 

 alcohol mixture is thus seen to differ materially from that for the 

 methyl-alcohol mixtures. 



COBALT CHLORIDE IN PROPYL ALCOHOL WITH WATER. 



Four propyl-alcohol solutions were prepared containing cobalt 

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

 by Ci in table 13, was 0.3 for each solution. The concentrations of the 

 water, denoted by c 2 , were 1.11, 2.78, 5.55, and 6.67. The values of a 

 for the pure-alcohol and pure-water solutions were taken from the work 

 on cobalt chloride in these solvents. 



As in the case of the methyl-alcohol mixtures, the pure propyl- 

 alcohol solution was a deep blue, which changed with the addition of 

 water through a series of purples, until the color became the pink hue 

 characteristic of the aqueous cobalt-chloride solutions. This change 

 was nearly complete for c 2 = l.ll. 



The a a curves (see paragraph on cobalt chloride in methyl 

 alcohol with water) show that as the amount of water present in the 

 propyl-alcohol solution increases the absorption at the edge of the red 

 band becomes less, and also that the edge of the infra-red band behaves 

 in a similar manner. The behavior of the edge of the infra-red band 

 is thus seen to be much the same in the cases of the methyl-alcohol and 

 ethyl-alcohol mixtures. 



