The beginnings and ends of shadow lie between the light and darkness and may be infinitely diminished and infinitely increased. Shadow is the means by which bodies display their form. The forms of bodies could not be understood in detail but for shadow.

The vivacity and brightness of colors in a landscape will never bear any comparison with a landscape in nature when it is illumined by the sun, unless the painting is placed in such a position that it will receive the same light from the sun as does the landscape.

All bodies together, and each by itself, give off to the surrounding air an infinite number of images which are all-pervading and each complete, each conveying the nature, colour and form of the body which produces it.

The variety of colour in objects cannot be discerned at a great distance, excepting in those parts which are directly lighted up by the solar rays.

Music cannot be called otherwise than the sister of painting, for she is dependent upon hearing, a sense second to sight, and her harmony is composed of the union of its proportional parts sounded simultaneously, rising and falling in one or more harmonic rhythms.

Shadow partakes of the nature of universal matter. All such matters are more powerful in their beginning and grow weaker towards the end, I say at the beginning, whatever their form or condition may be and whether visible or invisible. And it is not from small beginnings that they grow to a great size in time; as it might be a great oak which has a feeble beginning from a small acorn. Yet I may say that the oak is most powerful at its beginning, that is where it springs from the earth, which is where it is largest.