luminous rays strike between less equal angles will be less strongly illuminated.
SECOND BOOK ON LIGHT AND SHADE.
Gradations of strength in the shadows (148. 149).
148.
THAT PORTION OF A BODY IN LIGHT AND SHADE WILL BE LEAST LUMINOUS WHICH IS SEEN UNDER THE LEAST AMOUNT OF LIGHT.
That part of the object which is marked m is in the highest light because it faces the window a d by the line a f; n is in the second grade because the light b d strikes it by the line b e; o is in the third grade, as the light falls on it from c d by the line c h; p is the lowest light but one as c d falls on it by the line d v; q is the deepest shadow for no light falls on it from any part of the window.
In proportion as c d goes into a d so will n r s be darker than m,