CONFUSION OF POLARITY. 43 



the triangular prism of Newton, it must be recollected that 

 perfect light , when proceeding from an emanating point, appears 

 brilliant and white ; that when passing through refracting media, 

 it is exhibited in its prismatic COLORED rays of composition ; 

 and that the order of position and extent of the several colored 

 portions of the spectrum is influenced by the chemical constitu- 

 tion of the prism, as well as by its form. 



We shall for the present reason on the common angular 

 prism of flint glass, producing the three original colored rays of 



red, yellow, and blue, and the other four from intermediate 





 superposition. 



It must be evident that in the operation of refraction and 

 dispersion, the polarity of the original constituents is sensibly 

 deranged : they assume, instead of the triplicate compound, an 

 individual polarity, or one calculated to transmit a direct line of 

 homogeneous matter of the color exhibited in the given space 

 of the spectrum ; and the appearance of the dark lines may be 

 occasioned by those atoms which are unable to unite appro- 

 priately pole to pole in the individual lines, and are there- 

 fore non-luminous. According to a diagram exhibited by 

 Fraunhoffer, the dark lines are numerous in the red, and 

 orange, in the blue and violet, while they are but few in the 

 spaces occupied by the yellow and green. 



In the dissolution of white or perfect light into the three 

 original prismatic rays, it may occur that a confusion of polarity 

 has been produced in some of the rays, which do not undergo 

 perfect separation as to their constituent principles, and by this 

 convulsion, instead of retaining the appropriate polarity of 

 white light by the union of the positive pole of the one com- 

 pound molecule, with the negative pole of the next compound 

 molecule in succession, which, as appears by No. 6, Plate IV., to 

 be, as to the positive on the surface of that portion of the 

 spherical molecule occupied by the nitrogen yellow ray, while 

 its point of union is always with the negative pole in such cir- 

 cumstances ever to be found on the opposite surface, or that 



