OF COMMON MATTER. 163 



ception of those objects whence the light 

 arose. 



It is not surprising that matter .of this subtile 

 description should have evaded the inquiries 

 of the most enlightened and attentive ; and, 

 that they were reduced to the necessity of pro- 

 ceeding from assumptions, instead of axioms ; 

 and, of concluding from hypothesis, instead of 

 demonstration. 



The separation of a beam of atmospheric 

 color, through the medium of the prism, into 

 seven distinct parts, although not so antient 

 as the variegated colors, manifested by what is 

 called the rain-bow, is nevertheless, no modern 

 discovery. Sir Isaac Newton, in particular, may 

 be said to have nearly exhausted the subject. 

 It is, however, to Dr. HERSCHEL, to whom the 

 merit, unquestionably, belongs, of having sepa- 

 rated the element from the accident, the pure, 

 colorless light, from the compound and visible 

 color. As these experiments are detailed, at 

 large, in the Philosophical Transactions for 

 the year 1800, have been copied into dif- 

 ferent periodical publications, and are well 

 known ; I shall merely state the general re- 

 sult of them in this place, and refer the reader 

 to the original communication. When a prism 

 is properly adjusted, at a suitable distance from 

 a sheet of white paper, on which the spectrum, 



M 2 



