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 refiec- 
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 guaquaversus 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 direction, and therefore refiecting from their posterior surfaces 
a pencil of light with quaquaversus polarisation. 
Sr LEoNARD’S CoLLEGE, St ANDREWS, 
January 30. 1846. 
