Its contrary prevents the further passing, And thence the foreign radiance is reflected, Even as a color cometh back from glass, The which behind itself concealeth lead. 1229 Now thou wilt say the sunbeam shows itself More dimly there than in the other parts, By being there reflected farther back. From this reply experiment will free thee If e’er thou try it, which is wont to be The fountain to the rivers of your arts. Three mirrors shalt thou take, and two remove Alike from thee, the other more remote Between the former two shall meet thine eyes. Turned towards these, cause that behind thy back Be placed a light, illuming the three mirrors And coming back to thee by all reflected. Though in its quantity be not so ample The image most remote, there shalt thou see How it perforce is equally resplendent. Now, as beneath the touches of warm rays Naked the subject of the snow remains 1230 Both of its former color and its cold,