A luminous body will appear more brilliant in proportion as it is surrounded by deeper shadow. Leonardo da Vinci
A single and distinct luminous body causes stronger relief in the objects than a diffused light; as may be seen by comparing one side of a landscape illuminated by the sun, and one overshadowed by clouds, and illuminated only by the diffused light of the atmosphere. Leonardo da Vinci
No small hole can so modify the convergence of rays of light as to prevent, at a long distance, the transmission of the true form of the luminous body causing them. Leonardo da Vinci
A luminous body when obscured by a dense atmosphere will appear smaller; as may be seen by the moon or sun veiled by fogs. Leonardo da Vinci