Page:Principles of Microscope.djvu/37

 Rh reacquaint, himself with the physiological phenomena which come liere into consideration. He will find in Figs. f and g, Plate II, dark outlines laid down in the one case upon a blue in the other case upon a red field. Viewing these outlines through the covering tissue paper, it will be observed that they assume under the influence of the uncoloured light which radiates from this into the eye respectively a yellow and a green tint. In a similar manner, the dark margins of the glass filaments represented in Fig. k assume, when looked at through the covering tissue paper, a distinctly yellow tint. These are only illustrations of the general law that where we have disposed upon a coloured field a darker area, this area will, under the influence of uncoloured light reflected from its surface, assume in each case a tint complementary to that of the enveloping field.