WITHIN SOLID AND FLUID BODIES. 



121 



by the refraction of the dispersed light at the surfaces of the reflecting particles, 

 because such an action would only reduce the amount of polarisation by reflec- 

 tion ; and I have found by direct experiment, namely, by making the blue light 

 pass through different thicknesses of the fluid, that such an effect is not produced. 

 Unless, therefore, we suppose that this quaquaversus polarisation is a. new property 

 of light, produced by a peculiar action of certain solid and fluid bodies, we are 

 driven to the conclusion, no less remarkable, that it is produced by an infinite 

 number of doubly refracting crystals, having their axes of double refraction lying 

 in every possible du-ection, and therefore reflecting from their posterior surfaces 

 a pencil of light with quaquaversus polarisation. 



St Leonabd's College, St Andebws, 

 , January 30. 1846. 



