HOMOGENEOUS FLUIDS BY POLARIZED LIGHT. 65 



and impresses on the luminous rays, at their entrance and their 

 exit, the same modification which they ai'e subjected to by double 

 total reflexion in the interior of transparent bodies. The defi- 

 nition of these modifications in the present state of the theory 

 is sufficiently complicated. It is possible however, that after 

 all the hypothesis may be more simple than it appears. It is at 

 least certain that the pheenomena cannot be more simply repre- 

 sented than by the general formula 



F.cos [i + TT (e — o)], 

 to which this hypothesis has led me. It seems to me very pro- 

 bable, consequently, that this formula is really the expression of 

 the resultant of all the various movements of the luminous waves 

 in the oil of turpentine. But it is possible that these elemen- 

 tary movements do not take place precisely in the manner that 

 I have supposed. However that may be, the theory which I have 

 just advanced has the advantage of connecting the colorization 

 of homogeneous fluids in polarized light with the same princi- 

 ples as those upon which the colorization of crystalline lamina; 

 depend ; it indicates the points of contact in these phaenomena, 

 which differ so much in appearance, and in this respect, it 

 appears to me, it may be of some utility to science. 



VOL. V. PART XVII. 



