_Leonardo's theory of colours is even more intimately connected with his principles of light and shade than his Perspective of Disappearance and is in fact merely an appendix or supplement to those principles, as we gather from the titles to sections_ 264, 267_, and _276_, while others again_ (_Nos._ 281, 282_) are headed_ Prospettiva. _A very few of these chapters are to be found in the oldest copies and editions of the Treatise on Painting, and although the material they afford is but meager and the connection between them but slight, we must still attribute to them a special theoretical value as well as practical utility--all the more so because our knowledge of the theory and use of colours at the time of the Renaissance is still extremely limited._ The reciprocal effects of colours on objects placed opposite each other (263-272). 263. OF PAINTING. The hue of an illuminated object is affected by that of the luminous body. 264. OF SHADOW. The surface of any opaque body is affected by the colour of surrounding objects. 265. A shadow is always affected by the colour of the surface on which it is cast. 266. An image produced in a mirror is affected by the colour of the mirror. 267. OF LIGHT AND SHADE. Every portion of the surface of a body is varied [in hue] by the [reflected] colour of the object that may be opposite to it. EXAMPLE. If you place a spherical body between various objects that is to say with [direct] sunlight on one side of it, and on the other a wall illuminated by the sun, which wall may be green or of any other colour, while the surface on which it is placed may be red, and the two lateral sides are in shadow, you will see that the natural colour of that body will assume something of the hue reflected from those objects. The strongest will be [given by] the luminous body; the second by the illuminated wall, the third by the shadows. There will still be a portion which will take a tint from the colour of the edges. 268. The surface of every opaque body is affected by the colour of the objects surrounding it. But this effect will be strong or weak in proportion as those objects are more or less remote and more or less strongly [coloured]. 269. OF PAINTING. The surface of every opaque body assumes the hues reflected from surrounding objects. The surface of an opaque body assumes the hues of surrounding objects more strongly in proportion as the rays that form the images of those objects strike the surface at more equal angles. And the surface of an opaque body assumes a stronger hue from the surrounding objects in proportion as that surface is whiter and the colour of the object brighter or more highly illuminated. 270. OF THE RAYS WHICH CONVEY THROUGH THE AIR THE IMAGES OF OBJECTS.