104 COSMICAL PHENOMENA OF LIGHT. 



effects; while the various powers of different 

 bodies to decompose white light by absorption, 

 transmission, reflexion, refraction, and polariza- 

 tion, cause an endless diversity of colours. Light 

 then is not only a revelation of all that is grand 

 and beautiful in the outward universe, but the 

 agent by which all its operations are carried on. 

 It is therefore probable, that when fully under- 

 stood, it will enable us to explain whatever is 

 now mysterious in the ultimate mechanism and 

 laws of nature. 



And if " the particles of light be indentical 

 with the ultimate atoms of ponderable matter," 

 (the Tr/owVi? v\rt of the ancients,) the question natu- 

 rally arises, whether all the planets and satellites 

 of our system may not be so many masses of 

 embodied light, which is first aggregated into 

 nebulae, and then into comets, that go on gradu- 

 ally augmenting in size, by constant additions 

 of light, until after enormous periods of time, 

 (compared with which our geological epochs 

 are mere fractions,) they arrive at maturity ; or 

 until, by the expenditure of his substance, the 

 sun is so far reduced in magnitude, that the cen- 

 trifugal power of his rays becomes inferior to the 

 centripetal pressure of the surrounding aether 

 when they would gradually approach, and finally 

 in succession fall into the sun ? In short, whether 

 the ponderable matter of the sun and fixed stars 

 is not perpetually expanded by caloric into the 

 subtile form of light, which is as constantly re- 



