Ml. C. Lea—Influence of Color upon Reduction by Light. 201 
salt by particular rays be modified? And if so, will it follow 
sensibility of the reducible compound will be exalted to those 
rays which are absorbed by the body placed in contact with it? 
0 solve this question, I have made an extended series of 
experiments. But I have not been able to verify the existence 
of such a law. The results which I have obtained are briefly 
as follows: 
Ferrie Salts. 
product may contain ferrous salt, even a trace of which renders 
a 
im commerce of suitable shades. The other colors were 
obtained by dissolving suitable transparent pigments in varnish 
and coating glass with it. With the aid of aniline colors and 
Sort of artificial spectrum, under which papers of different 
Preparation could be simultaneously exposed. It is evident 
at in so . . 
th 
