222 



EQUATIONS OF MONOCHROMATIC LIGHT, ETC. 



While the writer has aimed at a greater degree of rigor than is 

 usual in the establishment of the fundamental equation of mono- 

 chromatic light, it is not claimed that this equation is absolutely 

 exact. The contrary is evident from the fact that the equation 

 does not embrace the phenomena which characterize such circularly 

 polarizing bodies as quartz. This, however, only implies the neglect 

 of extremely small quantities very small, for example, as compared 

 with those which determine the dispersion of colors. In one of the 

 papers already cited,* the case of a perfectly transparent body is 

 treated with a higher degree of approximation, so as to embrace the 

 phenomena in question. 



See page 195 of this volume. 



