Page:On the various forces of nature and their relations to each other.djvu/73

Rh and green, coming and going most beautifully not that the mica is more transparent than the glass, but because of the different manner in which its particles are arranged by the force of cohesion.

Now we will see how calcareous spar acts upon this light,—that stone which split up into rhombs, and of which you are each of you going to take a little piece home. [The mica was removed, and a piece of calc-spar introduced at A.] See how that turns the light round and round, and produces these rings and that black cross (fig. 20). Look at those colours—are they not most beautiful for you and for me?—for I enjoy these things as much as you do. In what a wonderful manner they