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.