The Absorption Coefficient of Solution for Monochromatic Radiation. 35 



a 



,.0500 



3.00 

 A 



2.00 



1.00 



..064 



1133 



.02 



.04 .06 C 



CoCI 2 in Iso-amyl alcohol 



700 eoo 900 1,000 i.ioo i.zoo i.aoo///-' 



FIG. 10. The A-c and Absorption Curves for Cobalt Chloride in Iso-amyl Alcohol. 



DISCUSSION OF RESULTS FOR COBALT CHLORIDE. 



The study of cobalt chloride in water and alcoholic solution brings 

 out the following facts: 



For the region of the spectrum lying on the long wave-length edge 

 of the yellow-red absorption band, the A c curves show that A 

 decreases with dilution. The decrease in A observed in the case of the 

 aqueous solution is considerable, and in the case of the alcoholic solu- 

 tions this decrease becomes more and more marked as the molecular 

 complexity of the alcohol increases. Jones and Anderson 1 studied 

 solutions of cobalt chloride in water, methyl alcohol, and ethyl alcohol. 

 Plates 2, 4, and 5 of their paper show that (in the region of the spectrum 

 under discussion) A decreases with dilution, and also that this decrease 

 is much more marked for the cases of the alcoholic solutions than for 

 the case of the water solution. This is in accord with the facts brought 

 out by the measurements discussed in the preceding paragraphs. In 

 the region of low absorption between the two bands it is concluded 

 that A is constant with respect to c. As has been mentioned already, 

 in the section concerning cobalt chloride in propyl alcohol, the values 

 of a for the region between the two bands are so small that the values of 

 A are in many cases worthless. 



Carnegie Inst. Wash. Pub. No. 110. 



