The medium is best.
OF SMALL LIGHTS.
Again, lights cast from a small window give strong differences of light and shade, all the more if the room lighted by it be large, and this is not good for painting.
517.
PAINTING.
The luminous air which enters by passing through orifices in walls into dark rooms will render the place less dark in proportion as the opening cuts into the walls which surround and cover in the pavement.
518.
OF THE QUALITY OF LIGHT.
In proportion to the number of times that a b goes into c d will it be more luminous than c d. And similarly, in proportion as the point e goes into c d will it be more luminous than c d; and this light is useful for carvers of delicate work. [Footnote 5: For the same reason a window thus constructed would be convenient for an