102 DECOMPOSITION OF LIGHT. 



mitted the red rays of the spectrum to pass 

 freely through them, but absorbed and oblite- 

 rated the other rays ;* that blue media permitted 

 rays of the same colour to pass through them, but 

 absorbed the other rays ; and that green media 

 absorbed the rays at both extremities of the spec- 

 trum, but the red most where it verges to blue, and 

 the violet most where it verges to yellow. Nor is it 

 more remarkable, that bodies should absorb one 

 or more primitive rays, and reflect or transmit 

 others, than that certain elements of ponderable 

 matter should have an elective affinity for some, 

 and an antipathy for other elements ; the rationale 

 of which is doubtless the same in both cases, and 

 must be sought in the fact, that as the different 

 rays of light are of different temperatures, so are 

 the elements of ponderable matter associated 

 with different quantities of caloric. And it will 

 be found hereafter, that no chemical union of 

 bodies ever takes place without the transition of 



* If in our cathedrals, colleges, and other public buildings, 

 were judiciously placed a few windows composed of perfectly red, 

 yellow, and blue glasses, (to which might be added combinations 

 of these colours,) the mind would be elevated, refined, and 

 instructed, on beholding such a vivid display of all that is most 

 beautiful in light when thus decomposed, and reduced to its 

 primitive elements. Never shall the author forget the emotions 

 of delight and admiration he experienced on first looking at 

 the sky through a fine ruby glass, when it presented the 

 appearance of a vast dome of lurid flame ; and the whole face of 

 the earth, as if by enchantment, was suddenly dyed of a gorgeous 

 crimson hue. We little think how cheaply some of the highest 

 pleasures of existence may be purchased. 



