The Absorption Coefficient of Solution for Monochromatic Radiation. 63 



and 645/x/i, on the edge of the band in the yellow show that A increases 

 with dilution. Throughout the remaining region from 724/z/x to 

 1,095/x/i, which includes the weak infra-red band, A is a constant for 

 all values of c. 



a 



.0400 _ 



.0300 



.0200 



.0100 



.0200. 



.0100 . 



8 C 1.0 



(NH 4 ) 2 S0 4 -Fe 2 (S0 4 ) 

 inH,0 



i.o 



.8 

 .7 



H ? 



600 700 800 900 1,000 I.IOO///* 



FIG. 23. The A-c and Absorption Curves for Ferric Ammonium Sulphate in Water. 



An attempt was made to cariy out measurements on solutions of 

 ferric chloride. The attempt failed because the precipitate of ferric 

 hydroxide appeared in such quantities after the solutions had remained 

 in the cells for fifteen minutes that any measurements of a were 

 meaningless. 



