ON THE ABSORPTION OF LIGHT 



described the phenomena in appropriate terms, it will 

 be evident that a certain difficulty must attach to their 

 reduction under the dominion of any theory, however 

 competent, ultimately, to render a true account of them. 

 Where such evidence of complication and suddenness 

 of transition subsists on the face of any large assemblage 

 of facts, we are not to expect that the mere mention of 

 a few general propositions, like cabalistic words, shall 

 all at once dissipate the complication, and render the 

 whole plain and intelligible. If we represent the total 

 intensity of light, in any point of a partially-absorbed 

 spectrum, by the ordinate of a curve whose abscissa in- 

 dicates the place of the ray in order of refrangibility, it 

 will be evident, from the enormous number of maxima 

 and minima it admits, and from the sudden starts and 

 frequent annihilations of its value through considerable 

 amplitudes of its abscissa, that its equation, if reducible 

 at all to analytical expression, must be of a singular and 

 complex nature ; and must at all events involve a great 

 number of arbitrary constants dependent on the relation 

 of the medium to light, as well as transcendents of a 

 high and intricate order. We must not, therefore, set 

 it down to the fault of either of the two rival theories if 

 we do not at once perceive how such phenomena are 

 to be reconciled to the one or to the other ; but rather 

 endeavour to satisfy ourselves whether there be, in the 

 first instance, anything in the phenomena, generally 

 considered, repugnant either to sound dynamical prin- 

 ciples, or to the notions which those theories respectively 

 involve as fundamental features. 



