190 



THE GEOLOGIST. 



staajes of fixity is facilitated or impeded, and they are rendered 

 applicable to farther appropriate changes. 



The paper next contained a statement of the reasonings 

 and experiments proving the following analogies, between 

 simple elements and simple rays of light, viz : — 



The Red Ray . . Oxygen. 



The Yellov/ Ray . Nitrogen. 



The Blue Ray . Hydrogen, 



each of which primary rays possesses peculiarly distinct and 

 countervailing qualities. 



It was next proved that colourless surfaces of nearly homo- 

 genous construction, after being subjected to the rays of 

 light, become coloured according to the absorption of the se- 

 parate or combined rays; evidencing the agency of these 

 rays of light and the heat engendered by them in producing 

 and imparting colours. This was done by instancing in par- 

 ticular, the effect of light upon glass, upon the corolla of plants, 

 and the variable colours observed in one and the same flower 

 during different periods of the day, according to the degree 

 of light to which it is subjected. 



Having thus traced the affinity between these two consti- 

 tuents of all matter, the author next proceeded to illustrate 

 his views with reference to mineral substances, evidencing 

 their relation to the foregoing combinations, notwithstanding 

 the impurity (or multiplicity of parts) of their components. 



1. Nearly all the natural combinations of oxygen with an 

 earthy or metallic base, are of a reddish colour. 



2. Natural combinations of nitrogen with the same, are 

 yellow. 



3. Natural combinations of hydrogen with the same, are 

 blue or bluish white. 



Thus, even with a present doubtful knowledge of ele- 

 mentary substances, there is an apparent law of colour in 



